I think I am bi, but i'm not sure how much.

I have been having a lot of fantasies about men, but I don't feel attracted to them. It's more the idea of having sex with a man and being a bottom that really interests me. So it's purely sexual, but no romantic interests in men at all. Not to mention the fact that I am a very nerveus and anxious person who has trouble trying out new things, especially sexual things. Does anyone have certain tips or just advice on what could help me take the plunge?