No it won't hurt. My brother and i both started lifting weights at 13 and were both still fine. Just don't start out with more weight then you can handle. Start out light and slowly build up to heavier stuff.
not everyone is the same, usually it stunts your growth that young, I didn't start lifting till 18, however I ran a lot and did a lot of stretching before that age and I'm 6'3 215 pounds. its worth the weight kid