Cutting your toenail too short or rounding the edge of the nail can cause it to grow into the skin. Wearing shoes or socks that don't fit well can also cause an ingrown toenail. If your shoes are too tight, they might press the nail into the toe and cause it to grow into the skin. You can get an ingrown toenail if you hurt your toe, such as stubbing it. This can cause the nail to grow inward.
A rider can be of any height if he or she still can make the assigned weight, but it is generally limited to fairly short individuals because of the limits on a person's body. The average jockey has a light but athletic build, and body weight is anywhere between 108 to 118 pounds.
Height doesn't matter as much for the horses health, but it can affect how you feel when you ride. most 12 hand ponies will weigh between 600 and 700 lbs unless he is a draft mix then add 150 lbs. The average weight of a 14 hand Quarter horse is 900lbs. I would say something near 600 pounds. My 12.3 hh pony is about 650, and he's about as chunky as your pony.