Some suggestions about how you, a Muslim teenager, can deal with the Prom:
Tip #1: Be firm
Your strength and clarity about not going will take some time to sink in, but it will eventually give your friends a clear message: nothing they say or do will change your mind, period. It should also be made clear that this is not a personal insult aimed at them. You are simply trying to maintain your Islamic principles, and you would not be able to do that in a Prom environment, that's all.
You and they can still play soccer, go fishing or hiking, but the Prom is just one activity which you'll have to skip.
Tip #2: Plan an alternative
We need to see Islam as a cool alternative, not a loser alternative. After getting over the initial disappointment of not going to the Prom, go to Plan B.
Get a couple of your Muslim friends together (who aren't going either) and plan to do something fun and of course, Halaal. The possibilities are endless. Sports are always a favorite for brothers. For sisters, you could have an all-sisters get together at your place. Plan alternatives early.
Tip #3: Hang out with your family
It may sound strange to do this when the Prom is about being with your friends. But think about it:
For many, this could be one of the last happy, carefree occasions you have with your family before moving away to another city or province for university or pursuing a career with added responsibilities.
While the Prom may seem hard to beat, there are alternatives. It requires creativity and intelligence. If we start to see Islam's rules on Halaal and Haraam as challenges instead of obstacles in our lives, we will find ways of having good, clean, fun without feeling left out.