Agree with what a PP has said, don't confuse salary earned with wealth. There will be people out there earn £50k and feel rich, and others earning £150k who feel it never stretches far enough.
OP I mean this kindly, but you have already made some choices that decrease your likelihood of getting what you want. Having a child young is one - it's very difficult to work the kind of long hours often demanded by the highest paying career tracks, with a child at home - especially if you are single which I'm assuming you are, as you haven't mentioned a partner.
Dropping out of A-levels is another - for many top paid jobs entry into a graduate fast track is required, and whatever anyone thinks they do look at your A-level /pre-university grades. An access course does not have the same kudos.
You are now considering dropping out/switching from your midwifery degree onto a different degree. If you do this, you will already have incurred £10-£15k+ of debt on a wasted first year of a degree - that sort of debt takes years to pay off, further delaying financial comfort. Whatever you do, you need to stick with it.
Also understand: you already have a child. The chance of being able to get to the sort of financial position to pay for private school, in time to do so for a child already born, is very unlikely. Set yourself more realistic goals. The sort of people who earn enough to pay for private education tend to work intensively for 10 years after graduation to build their career, delaying marriage and children until at least early 30's. They are already earning the big salaries before having children. It's so much harder to build a career with young children.
Next: cars. Lots of financially comfortable people don't drive 'nice' cars. Because they are expensive, and depreciate, and are poor assets to throw your money into.
Honestly, set yourself a more realistic goal of achieving financial security for yourself and your DC. As a PP has noted, you need to keep outgoings, below incomings, and over time you will build savings and security, which feels pretty good.
I know you feel disheartened by midwifery but actually I think you should stick with it. Don't waste the year you've already completed. Finish the degree, get a job, and start building security, once you are working and earning you can explore some different avenues within healthcare to earn a more comfortable salary. NHS jobs at least are very secure, and come with a very desirable. It's not to be sniffed at. If you live in a less expensive area you can still enjoy a decent standard of living.