Is 2 years old mature?

I hesitate to say where I found this link, but it is worth the read, in my opinion. I have a 2 year old under saddle who is going to do nothing more than sit and walk a couple of laps around the round pen with me on his back until he is at least three. And a 1.5 year old that probably won't see ANY real under saddle work with a rider on her back until she is at least three. Both horses are well adjusted to carrying a saddle and have started work with hackamores / o-ring snaffles. There are tons of things to do with them until proper conditioning with a rider begins in a couple of years.

I realize people have differing opinions, but for me, this is a touchy subject.

http://www.webertrainingstables.com/ridingyoung.cfm