Girl girls, and some more girls

I recently had a moment where I really really knew I was a lesbian but I’m not sure how to tell anybody. I’m 13 and iv told people and my family I’m bisexual and my family said “oh it’s just a phase” “you don’t really know what you want” “it’s just hormones” but I really do know. Everyone will look at me differently at school but I have all these feelings and I want to tell someone really bad. Sometimes I feel like I’m going to explode because I don’t know how to express it. Most of the time I just feel lonely.