Charming 'coming of age' movie!
OK, first off, I'm 50. Secondly, I have a 15 year old son (as well as 12 yr old son, and 5 year old girl. Don't ask. "The doctor says you have the best birth control on the planet!" yeah, well...)
I wouldn't want my 12 year old to see it at this point, (although, odds are good he'd understand all the references), and I was somewhat disconcerted about the sex/language (what a prude I've turned into!), in the end it's a great story about high school relationships and moving on past high school.
If you're concerned, see it before your kids do.