many people just get too caught up in how fast their horse can go, or how high their horse can jump, or how long their horse can go. We should not push our horses to the "how much" limit. I know that most everyone on here loves their horses, they just get caught up in competition, they want to bet better than everyone else. They need to just stop and think about their horses health, safety, wants, and needs.
Start her out at 18" and work your way up from their slowly. 16 is not by any means a young horse, and she is much more likely to harm herself at that age, so school low and don't enter her in any really serious competition