Answer:
ooh i feel you :(
i would recommend speaking to a professional online if you really don't know.
pay attention to the people you surround yourself with and are influenced by. are they part of the lgbtq+ community? if so, you may just be around them so much that their personality is rubbing off on you; in other words, you may have gay or bi mannerisms, but you're not actually lgbt. if you think you're bi, ask yourself: do you really view girls, guys, and non-binary people the same way? some bi people have preferences, but their sexuality determines that they "like" everyone. if you feel like you're in a place where you won't be accepted (and you're sensitive to that kind of thing), as a teen, my advice is to wait. it. out. if you're one hundred percent sure you're lgbt, of course you can tell anyone you like whether they accept you or not, but your question makes it seem like you're not. boiled down, i think you should tell a very very trusted friend who won't mind or be offended if you think you're wrong later on. if you don't have that friend, make one! everyone's online right now with nothing better to do so go to an amino, or some groupchat service, and find someone who will listen to you. good luck bbg
ps. i know this answer took a lot of twists and turns and sounded complicated, but so is discovering who you are. just remember that you always have time to figure out yourself and that you can always experiment.