I have the same exact problem, and I'm also a senior in High School. I've tried relationships (three times) and every time they tried to kiss me I would get anxiety and slowly begin to start ignoring them and then altogether stop talking to them so the anxiety would go away. I'm trying to face it right now, and I found someone who I could tell my issues to. I tell him when he causes anxiety attacks and when he doesn't, and we've been going on from there. We're going at a really slow pace, but since he's so understanding, I'm able to try out the relationship. I suggest you find someone you truly think you can tell about your anxiety who'll understand. Best of luck.