I think many who have walked the path feel what you are saying Mikeandcris. It is that fear, an almighty one at that, of the calendar. You start playing that mindset game, okay if you do this and get injured (broken bone) add 6-8 weeks where does that leave you for I-Day?
Right now a broken bone if it was to occur today, could place your child on medical turnback.
I would be like Mikeandcris, and I would say to them, enjoy life, but let's not push the risk factor, because if you do and get injured at best it is a DodMERB waiver or a turnback for a yr, worse, it is a medical waiver process that will impact your military career for forever. Injure the back and they can say no fighters for you since the ejection seat is a factor. Good, good friend played football for AFA, injured and was cleared for fighters. 8 yrs later playing flag FB with the squadron he was injured. Was never cleared to fly fighters again because of that injury...a squadron football game ended his career due to an old injury from his youth.
DD did barrel racing at 9 yo. It was common place in KS, so I get it. I get that everyone does it, if she was raised in NYC the sentiment would have been different. However, I have to say that it would be a no if this is the 1st time. Knowing a broken arm, leg, shoulder because they were thrown could risk the apptmt. would force me to lower the hammer and say hate me, call me a worry wart, or other names, but I am still the parent.