One question: is my sexuality the same? If it is then a whole world of experimentation and pleasure has opened up. The rest of my life is the same.
I guess it depends on if you define sexuality as a relative term (heterosexual, homosexual, bisexual) or as a directional term (I am attracted to women/men/both). Though for me, I haven't (so far) found myself to have any inclination, so I'd be just as neutral until I find out, in which case my friends may be weirded out if I find myself attracted to them (meaning I was gay before, and I probably had some subconscious feelings towards them while I was still male), or I'd be a gay woman, in which case that's a whole other can of worms (because finding a suitable partner becomes harder when the available candidates shrink by such a large amount).
OT: Technically gender is a social construct. The correct phrasing is "You are now the opposite sex". Unless you actually meant we had a huge personality shift putting us into the opposing gender role than the one we are in now ... I'm going to assume you meant sex.
Okay, so now my nit-pickiness is out of the way. I'd probably have to get some clothes (maybe borrow my brother's friends' bras so that I can actually go shopping first). After that, I'd probably need a new name because *Bio's Name* isn't very feminine, though I guess I could keep the initials the same, so people can call my *Bio's initials* rather than having to get used to a whole new name. Then being a teenage male turned female, I'd probably have to help my friends with the transition, as assuming I'm not butt-ugly, my friends (straight teenage males) will need to come to terms with the "It's Bio" feelings, and the conflict they will cause with the "Bio having female sexual organs" feelings.
So yeah, most of what I'll be doing (apart fom the initial shock and trying to figure out where everything goes) will probably be helping other people