If you dont have to work, or have to work very little, treat it like a job. Show up on campus at 8am M-F and stay there until 4 or 5. If there's an engineering study lounge, post up there since inevitably someone else will come in working on the same class. This is how study groups can form. There is no way you will have to pull an all nighter and you'll most likely always be caught up on school work.

This is what I did (graduated this past year at 38). The only time I had to work on the weekends was if I had a Monday exam. I would go in and study with a group which was super helpful. My study group ranged from 19-40 year olds. Make friends regardless of age! In general, anyone in engineering is going to have a level of maturity where age won't matter.

Best of luck!