Op you are trying to fix so many issues at once,....stop dreaming big and start making a (written to keep you on track) plan.
Uni is not necessarily the answer, if you want a type of job that works aroung your dcs then think about a trade, you could possibly train as a hairdresser and work freelance and build a business. I knew a Cornish mobile hairdresser who earned 30K around her childrens school hours!
Or nail technician doing shellac nails........find out about courses and grants in your area,
find a course that gives you a skill people pay for, that is not too long that will lead you straight into work at the end, study how to make a small business pay for free online.
To manage in the meantime, if your Dcs are at school or nursery work out what type of work you can offer, dog walking?cleaning?ironing? in my area all these cost £10/£12 per hour.
Save some money and put it into your chosen course, it may take a year or two but focus on the end game.....
Don't waste what you earn on non essentials, for household items use freecycle, ie rugs for your floors etc.
Use some money for an intensive driving course, often the best way to quickly pass your test. Once you have, don't get a car on finance, get an older low mileage basic car and pay in full.
I would say your focu should be,
Find easy income source you can do around Dcs
Save towards driving course
Pass test, save towards cheap car
Identify course to get trade qualification
Look for grants