People on this forum are very nice to babies.
My horse was broke at 2 and he's 8 now. We don't have any problems.
Use common sense. It is a young horse so don't ride for very long at all. I would use riding as a supplement to ground work and slowly begin to turn that around. In a year you could be doing both equally.
Don't do much more than walk and jog. His bones don't need any loping. Also, don't expect him to give you a really nice slow collected jog if he isn't naturally easy going. It requires more muscle tone than trotting quickly actually. Imagine trying to drive a car slowly in a higher gear. It requires a lot of torque. Conversely, trotting is a more aerobic exercise than jogging, so while his muscles wont need as much development, he might become winded easily. These horses are all 2 years old.