When I was 30 (3 years ago) I was in the exact same position as you, to the tee. I decided to go BACK to school and get another bachelor's degree in something I actually cared about even though I already had a master's.

Now I'm in my second year in a PhD program in a biomedical program.

Point is: a lot of us start to feel like we made a mistake and it's too late to fix.