We weren't even supposed to have any prom due to the sudden change in the curriculum. But almost everyone in our batch was eager to have one, including me, so we went on and stockpiled around 300,000 pesos (around $6500, school had no involvement whatsoever) just to organize the event. Even if I found the traditional events of prom quite tedious, everything else was a huge success and it was pretty much fun, especially due to the fact that we had full control over the entire event.
I can't blame OP for being sad that he/she isn't able to go to prom, even if the reason was kind of stupid and avoidable. I think it does matter since it's a huge part of one's high school memories, well, at least for me.