"gay" guy REALLY needs help

Hey guys, I'm a 23 yo man and I have identified myself as gay since I was 16. I have a nice sexual/romantic life (no major dramas) but lately I've been questioning myself about my sexual orientation. I recall being sexually and romantically attracted to girls when I was a young boy, but I never really dated any girl (I was rejected because I used to be fat) during then. Once I discovered bi porn I got increasingly interested in the male physique and one day I began watching plain gay porn. I first had sex some months after (after I lost a lot weight) with a older guy when I was 16. Since then I've been with many guys, had some longer relationships but hooked up a lot also (I'm mostly non-monogamist), and even kissed some girls but I've never had sex with a girl. But as I was getting to know myself better and experiencing knew things I also began "loosing" some stuff, I grew increasingly uninterested in girls, and the problem is that today I know even know how to tell a pretty girl from a ugly one, as I see no eroticism in the feminine body. When I talked to my best friend (who is gay and somewhat misogynist) about it my concerns he dismissed it saying I struggle with my sexuality because the conflicts I have home with my parents for they not accepting me. I understand his point, but I'm not so sure. There're things I never told him nor no one else (thanks interwebs for anonymity): mainly that I do not only do not feel attracted to girls and don't understand their eroticism, I do feel intimidated by women. I don't hate woman though, and I know I lose a lot by not being able to experience anything meaningful with girls (I don't even have girl friends!). As I found myself watching bi porn again (I don't usually watch porn in general, actually) these problems rose again, I fear that I might be repressing part of my sexuality out of the traumatic experiences of rejection by women of my childhood and early teens. I once read a psychoanalyst saying that sexual orientation is like a language, and we can learn how to be attracted to a multitude of genders. I know some people may disagree with her (by friend dismisses her by pointing out studies that indicate that male sexuality is overall stable and rigid after early adulthood, but I see her point: I do feel I forgot how to read female eroticism. Knowing there's so many nice girls out there and that I'm incapable of taking something positive out of it makes me uncomfortable. I do think I'm read to start experiencing knew stuff but i don't know how to begin. I know a lot about how to pick up gay and curious guys, I believe I'm a great lover and I'm completely capable of both starting something fresh with a new guy as I'm of hold a longer relationship (though I don't do mono stuff anymore), but I have NO IDEA how even to talk to girls, how to send and interpret their signs, how to make them comfortable and obviously not the slightest idea of how to please them. I don't want to just pick up a girl to try it because I think I would just be using her without being able to give something good in exchange, but I have no girl friends who I could open to and propose sex, for example. I tried using Tinder but the experience was terrifying (although I used it ok with guys). Does someone relates to my problem or has any idea of what I should do? Thank for reading it all!!!