Is being biual a bad thing? what causes it?

Im 22 years old and i think im .I come from a very religious family that i have never thought that this will happen to me. Is being biual somehow hereditary because i have cousin who is like that. I dont think that he have influence me in anyway because we are not really close to each other. I also plan to marry someday to a man. But the trouble is sometimes i think about women and having a relationship with them. I think i want both worlds but that is a bad thing right? I mean what am i? i never had a boyfriend or girlfriend before. Most of those who knew me ask me why i dont have a boyfriend. I dont know also. its weird that when im atracted to someone and i find out that they like me i somehow lose interest and feels awkward. Anyway any advise