If your grandson had been riding up a board to jump a small ditch, and doing it fine 14 times till he sprained his knee so he couldn't pedal efficiently and failed on the 15th try, I don't imagine anyone in the family would encourage him to try again until that knee was better.
As I understand it, (even though the situations are not exactly similar), that's what is going on with Biles. She's trying to find out whether her problem will gradually clear up.
   She HAS made mistakes before..in practice and in competition... and she always "covered her embarrassment" by being more careful next time as she hadn't noticed any lack of orientation in the air until that one event.
   The condition known as "twisties" is well known to others.... few of whom do tricks as dangerous as Biles.

I guess we'll see in a few months whether she is back on track.