No problem in sentiment; big problem in preening.
I’d kind of wonder where they are on Mary, if she was supposed to be sinless too, or even (as the bible DOES testify) “full of grace.” She’d understand what Jesus meant once He explained. That this Boy was spiritually serious enough to go to the temple, and that it was not His fault they lost track of Him. There shouldn’t have even been a fuss at that point.
Sentiment is all about preening - it’s always for the benefit of the audience. Everything he does or says is with an eye on the media.
Romans 3:23
Since he was sinless, why would he beg forgiveness?