Defender seems right
https://www.16personalities.com/isfj-personality
But maybe too on the nose?
https://www.16personalities.com/istj-personality
Answered how I would have when I was younger. Definitely also on the nose. I've come a long way as I've gotten older and matured and become more of my own person. Never would have dreamed I would have changed like this. Definitely for the better rather than me truly closing off people as I would have liked to have done.
I still see a lot of myself in the ISTJ but definitely isn't all of me.