right you said she is not inclined to sin and that leaving Him behind in Jerusalem was not sin/mistake cause she was “worried about her son” and finally found Him. So worrying is not a sin ( as is not leaving Him behind) ?
The text does not say that she left Him Behind in a careless way. He was a boy - firstly - and went off to preach about His Father and get involved. He was not sinning because He was on a spiritual errand, but in practical terms although He did not sin, He did in fact seemingly go off without telling his parents. Our Lady found Him.

She knows where to look, where to lead us, to find Him.

She did no wrong by giving her son room to be a boy and did no wrong by finding Him and even gently rebuking Him. A Mother is meant to correct her Son (in practical terms). Neither sinned. Mary was not expected to know where Jesus was but was expected to do what a Mother does and be concerned for Her son. No sin involved. Mary was not inclined to sin. It is all there if you look.
You have seen it and I am sure explained it accordingly. Just google “they thought Him beside Himself” and find biblehub with all the differing translations. Then read on and Mary comes into the picture.
Instead of looking at Biblehub on the internet go and grab some books by an R.C publisher or a decent Commentary, and do some proper research, as there are all sorts of translations out there and all sorts of dodgy ones at that.
That is an old tactic to label me incorrect without really correcting me, that is, show me what I am am missing of what took place at Calvary with Mary.
I am just saying how it is and Why should I do your research for you? Cardinal Newman did his own which led him to full understanding in the R.C Church. D.I.Y! It is more rewarding that way for you

I, on the other hand, I have no desire to go to in-depth, correcting your own insights. They are something between you and God. My only duty is to say the Truth in simple terms and this is the case for all Catholics when they see attacks against the Church, and yes, Our Lady and HOLY Mother. I am not on this forum to give myself a massive ego (or a headache) but to state what I understand to be the Truth against heresy. Then you can go and follow up yourself.
Look, enough cat and mouse. The CC finally made the Assumption a dogma of faith in 1950. To not believe it now is an authoritatively forewarned departure from the one true faith.
And what? The Hebrew Scriptures were not collated, or brought together rather, for centuries, does that make them invalid? The Bible was actually put together as one whole after a fair few centuries went by but we know the faith was there. In fact, the Gospels weren’t written immediately.
If one can’t get their head around a Dogma it is not a reason to jump ship. There was a Saint who couldn’t reconcile in (her?) head the Resurrection but the gift of piety told her it was her faith that was lacking not the belief. There was another Saint who was never shown one moment of consolation from God. One of the reasons Jesus came here was not to teach us how to be typical Pharisees and to help us massage our minds and tell us how great our understanding is but to teach us to have
faith and live by it.
Yes, she( Church/Pope) put forth many “proofs” from Tradition and some Scripture foreshadowing, dating back centuries. In 1950 most bishops were for the dogma but not all. So a generation or two ago I would be in some Catholic company, some.
There is nothing that can be argued about Dogma - written in stone. They are the sum of the Churches findings. The Church is a treasure chest of divine insights and reasoning…Go Dig! And enjoy!
Ask me something particular and don’t bring political rambling and politics into religious debate. Not interested. If you want to know something ask in simple and straightforward terms…what about Mary and Calvary? Are you going to argue “sola scriptura” at the end of this? Or are you open in your heart to Reasoned debate…?