Yeah I'm 18 and I used to do that. I've tried my best to come out of my comfort zone and even though I stutter, I enjoy contributing even if I stutter. You should give it a try, even if you only have a year left. I'm about to finish school forever and go onto university next year so I don't have those same opportunities but I suggest that you make the most of them. I've become a lot more confident and in control of my stutter as a result, even if I've been totally nervous and had a block for 10 seconds which may seem embarrassing but it really isn't. I'd like for you to try take on my advice and please let me know how it goes, I'd love to know!