First band, any advice?

My friend is starting a crusty type band and I have been invited to join, I play viola haha I know it's weird, but I've only played with my orchestra but that was in high school 4 years ago. Overall I've been playing for 10 years. I'm super nervous about being able to play in front of my band mates, and other people. I only have read sheet music and I know most bands don't use such things. Any tips for me? I'd be very greatfull :)