It's really not simple. I only realised I was a lesbian when I was 17 after thinking I was pan (and before that straight). Dont bother telling people if they are homophobic, but also I'd cut people like that out of your life or at least distance yourself from them. When you get older there will definitely be people who will be accepting of you. College and Uni are 2 of the most accepting places (and I go to a catholic college, so that's saying something) obviously it depends where you live.
Dont listen to internet tests only you can really tell how you feel, but look into other experiences of lesbians and bi women. Like what makes you think you're attracted to women. Sometimes sexually doesn't matter at all. Could you be in a romantic relationship with one? What makes you think you're a lesbian?
For me I only realised when I realised that I couldn't see myself in a relationship with a man and definitely not sexually. I used to think I had crushes on men, but in reality these were usually people other friends of mine had crushes on or had dated before.
It's an internal thing, and if you do choose a label (which you don't need to, you can simply just say 'i like girls' for now) then dont feel upset if it changes either.
Another thing is if the reason you think you're a lesbian is just because you aren't attracted to boys or if it's because you're attracted to girls since being lesbian isn't a lack of attraction to men but a sole attraction to women.