My advice is safety first. Horses are dangerous animals. Get a helmet. Get boots. Boots that will withstand getting stepped on by a shod horse. Nothing hurts worse than getting your foot caught beneath a horses full weight wearing shoes. The boots should have appropriate heels to prevent your foot slipping through the stirrups. God I could go on and on. Make sure the horse can be handled by another person before you get near it. If you've never been around a horse it's best to watch someone else interact with one to give you an idea of what to do. Let me know if you have anymore advice!