When to Start Riding Baby

Many people don't ride their young horses until they are three. They are worried about making their horse lame. That is a legitimate reason to not ride until they are stronger and have stronger, more stable, bones. I think that you can start riding before that. I started riding my fillies when I thought they were ready. I prepared them the best I could, and when I felt they would accept someone on their back I got on. That's way simplified, but that's the jist of what happened. The first time I rode those fillies was the fall of last year. Granted someone was leading. It was a very short session. They were actually less than two years old. Throughout the winter we didn't do a whole lot of riding. When we did ride someone was leading. Through most of the winter we worked on ground driving, just waiting for them to get a little bigger. We sat on them and got them accustomed to someone on their back. Our legit riding didn't take place until the end of the winter. Still less than two years old. We kept riding times really short. Less than ten minutes, and we never did hard exercise. Mostly it was walking, with a little bit of trotting. We kept circle work to a bare minimum. Doing lots of circles with a growing horse is bad for their joints. They definitely needed to know how to do it, they didn't need to be superstars at it. At two years old we were working on cantering. Cantering was kept to a minimum. Still no lameness issues. We limited the amount of work we did with them so that we could proceed faster. Over the summer we did lots of trail rides. Our shortest trail ride was 20 minutes, and our longest is three hours. We do not work them really  hard on the trails. Especially when we first started, we did very little cantering and trotting. Now we do quite a bit more of it, but they are stronger. We still don't do a whole lot of circles. We do work a little on circles, but we only do a couple of circles. We never drill it into them. Now I just want to say that our fillies are 2 1/2 and still have quite a bit of growing to do. They could still become lame, but we work to make sure they don't. The real test will be when they are five or six and still without lameness issues.
To sum this up if you want to start riding a horse early, keep things light and non-stressful.
That's my limited insight into riding young horses. I wish I had the experience of starting hundreds of foals. Unfortunately I don't. I could give you a more accurate and informed opinion on the subject if I did.

Prepare your Horse!
Lydia Johnson