Contact your child's school. This is the first place I would start. When my daughter was 13 she wanted an activity after school & there was limits the middle school had. So when I contacted the school they told me should could run cross country or track for the High School's JV team.I was worried that being around the older kids may be to much but it cushioned the change over for the High School because she new some older childeren. I has been a wonderful outlet for her. Not only the benefits of the physical activity but she has developed a love for running & she has told me that it is one of her favorate ways to clear her head & focus. She even started pole vaulting!
The second suggestion would be any local church. We volunteer to help unload the pumpkins for the fall pumpkin sale as well as sit the tent for selling them & the Christmas trees & festivals too. We dont even go to that church! If these things are not options for you or unavailable you could always contact your local town government & see if they have any recreational facilities or a YMCA. I hope this was helpful information. Good luck & take care!