We decided on 13 for our daughter... She's a rule-follower, and stays where she is "put," lol, so we were comfortable enough with the idea. Of course, we didn't just throw caution to the wind--first we left her home alone for a while, then let her roam small parts of the local mall alone, then let her roam the whole mall on her own, then roam small parts of the parks on her own. If, at any point, she didn't return on time, privileges would have been pulled back; contrarily, she was always about 5 minutes early to check-in, along with texting random things she thought I would like to see.