I don't think it was too much. But people generally base talking too much on how much time it takes and/or how much was said. If you were as consice with him as you were with us, then that's fine. If you took out a 30 page monologue on your life and getting bullied, then yeh, that was too much.
Had I bullied someone in school, and finally felt bad enough to apologize to them, and they didn't say anything back to me, I'd feel really terrible. So it is appropriate to talk about it a little bit, but as you said, not too much.
However, the most important thing (in terms of being "socially acceptable") is that you remembered to say "it's okay", "I forgive you", or "Thank you for the apology. It really means a lot to me."