I would not get on that horse's back before age two or even 2.5 (and then only light stuff).
And it won't hurt your horse to wait until age three. They develop mentally, too.
In fact, I have one colt that I didn't really get to as a three-year-old (had two other young ones, and ran out of time), so I'll start him as a four-year-old. I was feeling anxious about it, but he seems to be getting calmer as he gets older, so now I'm thinking it wasn't such a bad thing after all.
In the meantime, you can do some groundwork to get your horse ready.