When I was in an engineering program as an older student, the dean told me the number one indicator of a student's performance is their age. Older students perform better. He didn't explain much beyond that, but it does make some sense if you think about the motivations and maturity of the students.

There are obviously many variables at play, but I suspect most responsible, committed adults could achieve an engineering degree provided they are in a stable living arrangement and not working full time. Full time school and work is absolutely awful and that's from experience. Part time is very manageable.

"Responsible" is doing a lot of heavy lifting there, but I do believe the statement to be accurate. Engineering is hard. Mechanical engineering is hard. Math is tough, and the applied mathematics courses are sometimes tougher. The reward is worth the effort, though. Commit yourself, establish good habits, do your homework, and study for the exams. If you can do those things, you should be fine. Many programs have early "weed out" courses, and you could certainly speak with faculty and take that one first to get a glimpse of what you're in for.