My first girl crush

I am a 14year old female.

I remember i was pretty straight till year 11. I questioned my sexuality a lot and later I found out I am a bisexual. I was pretty sure about that, because woman attracted me a lot too, but I never had a crush 'cause all my friends were straight.

Year 14, I met a cute girl my age on internet and found out she is pansexual. We talked a lot about ourselves, we have same hobbies,likes. My crush appeared for her. It was my first crush on a girl and I am now 100% sure I belong to lgbt group.

But now the problem is that i don't feel attracted to men in any way, but I don't think is possible to go from straight to bisexual, from bisexual to lesbian. Or is it?

Edit: I also came out to my mom as a bisexual, but she thinks that I'm just mixing my feelings and I cant see the difference betwern love and friendship. My grandparents are big homophobic and wouldn't support me. I once talked about it with them but they said that i would just bring shame to my family.