Originally Posted by KatieQ
He was tripping in front, and he is extremely green so I am thinking his balance is not quite there yet. I am not heavy, but he is not in shape so was probably tired after the previous day's workout and the warm-up. He is also by nature a lazy horse!
It has nothing to do with you being heavy it is how the horse carries himself. If he is carrying his weight up front"heavy on the forehand" he will stumble.
This is elementary for some one teaching dressage and if they can't see that I would be concerned. You could post a photo and I could tell you.