Ok, so my story is high fantasy, set in medieval times. My MC is the crown prince and only child of the king (he is 15). Horse back riding is a big deal in the kingdom, the army is all mounted (no foot soldiers) military states is also a big deal. My MC falls of of his horse during the Games (a big festival held every year, to celebrate the military.) He sustains a bad injure to his back, as well as a head injury. The head injury causes him to have seizures. Basically I ruin my MC's life. I need to know if what I have come up with is even possible. And if it even sounds like a good idea.