Welcome! There's actually lots of young users on here. 19 here and many 18 year olds. I've had mine since I was 12 though
I'd suggest:
- different headlights
- different rims, I think you'd like something fatter on the back with maybe a nice dish. It'll make a huge different to have something flush in the back.
- lowering springs
- wingless
- lots of the guys like the chin spoiler on the stock bumpers. Its a hit and miss with me with that.
- painted mirrors
Performance:
- rear end gears, good bang for your buck if you're on a tight budget
- supercharger if you're willing to spend more money.