How to meet older teen guys outside of school?

The guys in my school are all really immature. I'm 16 and I want to date older guys, around 18. I just feel more comfortable talking to older guys and feel like I have more in common with them. I'm pretty shy, but if someone approached me who was cute I would talk to them for a bit but I would still be a bit reserved. But so far that hasn't happened, but I want to know how I could meet guys outside of school? I'm into artsy guys, guys who are eccentric and a bit off beat (guys with piercings, weird hair, but sweet at the same time). My close friends always get annoyed if a guy they don't know talks to them so it's hard for me to talk to a guy with my friends. I'm too shy to approach anyone, especially if they were older than me since I look young for my age. I already hangout in coffee shops and go to concerts, but a lot of the guys are with a big group of people so they don't really notice me. I've never had a boyfriend, because i've never met anyone I really like, and i'm a bit odd compared to others girls (personality wise). Most people assume i'm a good girl and that i'm innocent yet I am quiet the opposite.