It could have been the way you were raised. However, I do not think your transgender, just very girlish in your mannerisms. Also, being bi is totally different than being purely gay. I have had a couple of male friends who were bi and a bunch more girls I know are. They all seem entirely different than gay people and most of them pretty much are into the opposite sex far more than the same sex, it seems that they (at least all the people I have known who said they were bi) usually just from time to time dabble with same-sex activities. So, even though they say being gay is hardwired, I don't think you were necessarily hard wired this way. Maybe the environment was a big contributor.