Not to mention she literally has a line afterward where she tells Finn that she's flown before, just not in space.
Which brings me back to my "did my theater and BluRay copy have a manufacturing defect because we didn't watch the same movie" argument.
Not to mention the fact that from the very beginning of the franchise in a New Hope, they establish that part of being strong with the Force, is to let it flow through you. Ben flat out says this to Luke when he's doing the deflection training.
"Remember a Jedi can feel the Force, FLOWING through him!"
Luke: "You mean it CONTROLS YOUR ACTIONS?"
Ben: "PARTIALLY. But it also obeys your commands."
This very fact, is why Luke, without any actual melee training, or blind fighting training was able to, after just a handful of errors, perfectly predict and block a series of blaster shots on day 1 of training. The whole point of the Force philosophy is that if you let go of your conscious self, and act on instinct (the very words Ben uses to try and get Luke to start using the Force), you can accomplish amazing things. And we see this time and time again in the various iterations of the franchise. We see Ezra instinctively using Force Leap to escape the troopers in the first episode, which is what makes Kanen notice him to start training him. We see him instinctively use Mind Control in a later episode when he accidentally taps into the Dark side. Hell CHILD Anakin regularly takes part in insanely fast racing events, and the Jedi clearly indicate the reason he's so good, is he is unconsciously tapping into the Force to give him an edge. And tons of other examples from the franchise. I mean hell Baby Yoda is able to Force Heal someone and he's established to be a BABY! We see Luke send Leia a Force Tweet without any training, or indication that it was possible, we saw him use the Force to move an object to him to get his lightsaber, despite any indication up to that point he knew it was something he could do. So it's hardly without precedent for a fledgling Force user to excel at activities that they don't have practical experience in, or are good at something BECAUSE they are instinctively using the Force. Or pull new abilities out of their ass Because The Force.
So the idea that a woman who is established to have some melee skills due to living on the streets, being able to temporarily out perform a guy who isn't trying to kill her anyway, suffering from a critical gut wound from a boltcaster (a weapon that is established to normally FLING TARGETS BACK 40 FEET AND EXPLODE) and suffering emotional instability from patricide....yeah, I don't think it's unreasonable for her to be able, at the climax of a film, as the protagonist, to get the upper hand on the antagonist and win. It's hardly a unique situation to Rey, or even the Star Wars franchise itself.
They changed the phrasing in Force Awakens with Rey, but the "let the Force flow through you" is reinforced through Maz Kanada's line about "let it in." Stop resisting it's influence and harness it. The Force is a HUGE hand wavey magical plot wand that has been used, for DECADES to justify all kinds of things that in other settings would be problems, but "It's the Force, I don't have to explain shit." Is an entirely valid reason in Star Wars.
Now I do think it's a little fuzzy about her piloting skills, based on the lack of indication to it. The line you are referring to, about where she tells Finn that she's flown before, but not in space, was that during the part where they were both talking really fast to each other in an excited manner, right after escaping the tie fighters? If so, then I can forgive people missing it, because it is very hard to follow both dialogue lines when they are going at the same time. So that's not the best time to convey a bit of information. Though I personally don't care too much. But, if one line of dialogue is good enough to establish Luke as being Fighter Pilot Ready in New Hope, I don't see what the issue is with it being established with the same level of detail with Rey. It would be better to show not tell, but they didn't show with Luke either so...*shrugs*
My preferred way of dealing with this, would've been a single quick exchange of dialogue when she's going to get her first set of meal rations. Where that guy says something like "Hey I need you to fly that *Insert Ship Name* over to the scrapyard in *Insert Town Name*" Rey: *Looks annoyed and frustrated* "Again? I just flew one of your scrapheaps over there yesterday! You know it's a hard walk to get back here from there!" Dude: "I don't care, I mean if you don't want your rations" *pulls away the food* Rey: *slapping her hand down on the food* "No no, FINE. I'll fly that T-69 Floopstooper over to Yaboo Noknok after I eat, ok?" Dude: "Deal, now get out of here"
That would, at the very least establish it as much as they did in New Hope. They did SAY he was at least passably skilled at piloting on 3 occasions that I can think of in New Hope. Ben comments about "And I hear your something of a pilot yourself." When talking about Anakin's piloting skills. Han mocks Luke in the cantina scene when they are discussing prices "10,000?! We can almost buy our own ship for that!" Han: "And who's gonna fly it kid? You?!" Luke:"You bet I could I'm not such a bad pilot myself!" And then the "I used to bullseye womprats in my T-16 back home" All 3 lines TELL us, but don't SHOW us that Luke is a good pilot, and then the first time we see him actually fly, is in a combat situation in the middle of a military assault on a fortified base.
Whereas Rey, is SHOWN to have skills at flying. But, I mean do you all literally need to have it spelled out to you? You are joining her story 19ish years into her life, where she has clearly had to learn a large set of skills to survive in a hostile environment, to make herself useful. They show that she is good at flying, with just as much lead up as they had for Anakin and his pod racing. I've just, I've never understood this problem, the film provides, at the earliest opportunity, visual proof of her abilities, and people act like they need to see her fucking pilot's certification papers and license before they will accept that she is capable of doing ANYTHING!
Also, I've never really seen a problem with the idea of people just being knowledgeable in how to fly starships. They are portrayed as being as ubiquitous as cars, so the idea that random people just know how to fly them isn't weird. I mean hell, 2 of my friends growing up were huge car junkies, and they had tricked out cars, and were quite good at racing and speed driving. But you wouldn't know it from looking at them, because it's not like they came with a sign over their head that said "COMPETENT AT COMPETITIVE DRIVING"
When I first saw Rey mucking about in a crashed ship, and then showing up at a salvage/scrap yard, and showing clear knowledge about machine and vehicles, my brain just said "Oh, ok, she's a gearhead." Which pretty much just assumes you are above average skilled in vehicle operation and maintenance, because that's what that Trope almost always conveys. It's very strange for people who are that knowledgeable about the workings of a vehicle, to be clueless about the operation of it. They are, in my personal experience, almost one in the same.
So yeah, I don't see any real issue with Rey's implied skills in Force Awakens. Could it have been better established with a few more lines of dialogue? Maybe, but it's not like they put a lot of work into establishing Luke's credentials either, and everyone was fine with it.