At this point in your life, it's hard to stay home when people you know seem to be out having fun. After you graduate, many of these same people will be going nowhere in life because they got caught up in partying. I know it doesn't feel like it, but she is doing you a huge favor. I never imagined a world where many years later I'd actually appreciate my parents being strict. I did NOT appreciate it and was pretty mad while it was happening.
There's a story about these kids who wanted to go to a party but their mother wouldn't let them, what most kids their age did was go anyway, so they did, to make a long story short, the building/house ended up on fire and they died. I'd listen to my mom if I were you
Try understanding her point of view. If you had a choice, likely you would prefer to swim at a beach that is manned by lifeguards. Why? Because while you're in the water having fun, your awareness of danger is very limited. But lifeguards have a better vantage point from which to spot hazards. Similarly, because of their greater knowledge and experience, your mom may be aware of dangers that you do not see. Like the lifeguards on the beach, your mom's goal is, not to spoil your fun, but to help you avoid dangers that could rob you of enjoyment in life.