Sexual attraction i first clearly noticed during puberty. At least up to the age of about 24 years, it has however always been the case, that i tended to get along better with girls, than with guys - i don't mean regarding love, but in general. This however may have been for reasons related to something else:
I've never felt "manly", nor did i ever feel "girly" - regarding gender. It was more like i just did and feel whatever came to my mind at the moment, and what was important to me at the moment. So, in one situation i may have acted and felt similiar to what's called girly, in another situation more closely to what's called "manly", and most of the time, i'd act and feel like "something else".
The reason why i at first got along better with girls, i think had to do with the boys i knew having a tendency to "show off" and be clearly ... how should i describe this.... rejective of their own selfperception. With girls, that wasn't the case - when talking with them, there was no need to establish some kind of hierachy or pretending something - both could just talk about whatever seemed interesting at the moment, without the need of pretending something. I think that's why at first i got along better with girls, even though i wasn't biased towards female gender behaviour.
Later on, that bias got corrected back into balance, for multiple reasons: One being that i got better methods for finding guys that are not "typically manly". Second because i developed communication methods to reduce such biases among the other person. Third because if misc disappointments with girls. And finally because i began to notice annoying systematic biases with girls - so that then, girls as well as guys to me had biases alien to me, just different ones.
Hmm, that was a lot about gender, even though the topic is about sexuality. Oh, i almost forgot: I'm straight.