I taught my son the same prayer when he was born
Do you consider yourself very religious?
Well, not really. I just wanted him to be a noble boy.
I see that you wanted to teach your son good values, and it's great that you taught him the value of prayer. Just make sure you continue to be a good example for him, or he might remember the prayer, while not acting in a way that is consistent with it.
My son is already noble so I don't have to worry about it.
In that case, I'm glad that your son has grown up to follow your good example.  As long as you continue to be good role model, I'm sure that your son will live a noble life, just as you wanted.