Parents never let me go to parties?

Alright, here is my problem. My parents very seldom let me go to parties that i want to. I would have to get an invitation weeks before the actual date. For example today my buddy was having a party and he is 3 years older then me. Lots of my friends were going and there probably was going to be beer. I couldn't go. The thing thats really frustrating is that i haven't done anything bad to lose there trust or anything. And right now i just feel like rebelling. Its pissing me off because I'm losing lots of friends i had because i never go to these functions. I know eventually my friends will stop inviting me because I'm seen as the kid who always has an excuse. I just want to go to a couple so people know that I'm not just some kid who sits home on the computer. I am 16..and feel like high schools almost over and that i really haven't done anything or had any real friends because i never go to these parties..I kind of see what my parents are saying but cant they see my point. im pissed.