I didn't want to go to my prom because dressing up just stresses me out, and I just really couldn't be bothered with it - it's not my thing. However my boyfriend at the time wanted to go, and then I got what is in my opinion the prettiest dress I'd ever seen, and I ended up kind of looking forward to it.
Fast forward to prom, I spent the whole first half of the day crying because getting ready was so stressful and I couldn't shave my legs (I still can't, without is being excruciatingly painful and them breaking out in nasty spots), my dress wouldn't stay up, I didn't feel like part of the group, I had no idea how to do make-up (and, you guessed it, I still don't). I ended up going with my then-boyfriend's group and basically ended up barely seeing my friends because they were all on a different table. Everyone left right after the meal to go to a big party so the hotel was practically deserted. The food was so awful that I ate nothing all night, the pictures I sent in for this thingy didn't go through, my then-boyfriend didn't want to dance, then we left around 11:30, had a tiny bit of gin (or tonic, I can't remember), then I got into an argument with my then-boyfriend and slept on the floor.
Basically I felt like crying the whole night. It was nothing like the kind of prom you see on TV, and it just really wasn't my scene. I spent £40 on a ticket, £35 on a dress, and £20 on shoes, and ended up wishing I'd spent it on a telescope or books or literally anything else.
Will I go to my Year 13 prom? Yes. It's supposed to just be a classy dinner - no big dresses or fuss. The only reason I'm going to go is because I want a do-over, and pictures with my best friend, and a night that doesn't make me feel awful looking back at it. And I am bringing a big-ass tuna mayo sandwich with me.
Conclusion: don't not go just because you don't like some people in your year. But if you decide to go, make sure you have some good friends that you can spend it with. Otherwise it will be kind of ****. On the other hand, if you find the idea stressful, like I did, relax at home and do something you like.