I probably would be making a big mistake to come out and then be wrong about it! Is it possible to learn to like girls? Or am I stupid for even thinking such a dumb thought?
You aren't stupid for thinking or trying it. I am fortunate in that my friends are highly sexually diverse so when I 'came out' with regards to my bisexuality I received no hostility - quite the contrary, I got a lot of support. I have not discussed it with my parents, for reasons I will reveal.
First though, about the learning to like girls thing, when I came out I was quite young (16 I think), and I thought that I should try and like men in equal quantity as I do women. I felt bad that this wasn't the case and really really tried to do it.
After several years I came to the following conclusion: I find attractive whoever I find attractive. I don't worry if that is a male person or a female person, if I find them attractive I don't repress that feeling - I experience it.
I identify as bisexual if asked because I feel I find men attractive more often than people that identify themselves as straight. However, in anonymous surveys men who identify themselves as straight routinely admit that they have homosexual fantasies from time to time.
As to why I have never told my parents about it? Because I feel as nonchalant about it as described above, I just find attractive people attractive regardless of gender. There is no need to tell my folks this, my sexuality is my own affair. My parents certainly never told me their sexuality nor have they enquired into my own. It is a different story if you are planning on getting a boyfriend of course - it is only polite to warn your parents before bringing him over but I live away from home now, so I never needed worry about that.
As indicated, I am fortunate that I have no frame of reference to really understand your position. I have some family in Louisiana and I can somewhat appreciate the extent of the cultural aversity towards homosexuality there. As such I can give you no good advice as to what to do with regards to your friends and family. All I can offer you, is the nugget of wisdom I only gleamed after years of searching: Find attractive whomever you find attractive.
I truly hope your social/familial problems are resolved satisfactorily.