If our brain doesn’t believe the new thought, does that mean our unconscious beliefs are still running the show?

Hi, I’m confused about something. I get changing our T’s which create different F’s, A’s and R’s. But how do we know if we are really believing the new T? Is it by how we feel with the new thought? What if our brain doesn’t really believe the new T and so our unconscious T is still running in the background continuing to create old F’s, A’s and R’s? For example; I’ve had a T for such a long time about being 52 and not owning a house which I make mean, “I’m not an adult and not a worthy human, etc.” I’ve asked for help here and a suggestion was given to say, “I don’t have a house yet but I have a home!” So I’ve been practicing this a lot but in my TD today, I noticed my original T is still humming in the background. As if my brain is saying, “practice the new T all you want but you are still a child and not worthy!” I hope this makes sense?