I think God meant what he said..
Your own catechism says only Christ could keep the law perfectly..imperfect keeping of the law is sin..
Ergo Mary could not have kept the law perfectly and therefore she sinned like ALL men
I know what you think. And I know how we all confuse what we heard with what somebody said.
AND I know that many on your side wouldn’t know a tertium quid if it bit them on the, ah, nose.