Don’t worry, Cassie, it’s not too late to teach your horse how to be ridden. You should have no problems teaching him.
By the way, I would love to use this opportunity to share a little pet peeve of mine: the word “break” when discussing training horses to be ridden…which “breaks” my heart! You see, the term comes from the phrase “breaking [his] spirit,” which is not what we want to do in any way, shape or form. We are simply teaching him or her to accept a rider. By removing the term “break” from our horse vocabulary, we can help decrease the likelihood that someone with little understanding will feel the need to break a horse’s spirit.