By the demographic represented in this thread, I'm an old fart, albeit one who took his 15 1/2 year old son to this show. We both loved it, and neither of us was seriously uncomfortable in the other's presence.
Parents, go for it. Kids, take the folks. It's a show about teenage feelings -- awakenings, yeah -- but it's not a show "for" teenagers, and it's not shaped as though formed with "insider" POV. It very seriously portrays a universal experience, coming of age, and explores it with great theatricality, style, and brimming emotion. Older people might find more to relate to here than in GREASE.
Young love and the attendant angst has been the stuff of musical theater from its inception. In many ways, it's closer in spirit to WEST SIDE STORY than, say, RENT. And it's not about a rarified world -- druggies on the lower east side. Anyone resisting should give it a chance.
"I'm a comedian, but in my spare time, things bother me." Garry Shandling