Gonna be tough. 93 units, working full time, quitting job, supporting family? It's going to be incredibly tough on you and the family. I mean it can be done...but is it worth it?
I guess I can sorta relate. My parents never had the chance to go to school etc. They had to work full time to make ends meets; however, they always wanted to do something they enjoyed (I.E. Dental School, and I'm sure they thought about it as they were raising me). Yet, the sacrifice of quitting would be to much of a burden on the family and unrealistic (although it would of been possible to succeed). None-the-less, they instilled to me the importance of education and through their advice, I lived out their dreams. I guess I gotta give major props to my parents for sacrificing for me.
That being said, its never to late to start school/new career. After I was situated in college/independent, my parents went back to school to pursue what they wanted, because they were freed of their obligations. My Mom went on to get her masters, and is enjoying life in the health field as opposed to working a 9-5 clerical job. I've also met 50 year old medical students who went back to school after they finished situating their kids/families.
It's never to late to go back, so don't think that if you can't do it now, it will never happen. If anything, impart the wisdom to your kids, and whichever choice you make, it will be a good one. Good luck with your decision.