What if my crush is the same gender as me? I always see her in my class, and I think it's obvious that I have a crush on her.

There's nothing inappropriate about having a same-gender crush, despite what you might have been told in the past. Being attracted to someone of your gender may seem uncommon, but it's actually more common than you'd think, and there's nothing wrong with being gay, bi, or any other sexual orientation. If you really want to, you can get over your crush, but it might be better for you to seek out support and resources for LGBT+ people, particularly if you're still questioning or worry about a lack of support in person. In your case, it may also help to take a look at How to Deal With a Same Sex Crush (Girls) to help you cope with your feelings.