I personally found working in a salon invaluable and i would really recommend it before starting up on your own...even if just for 6-12 months.
You don't realise until then, how little you actually know on a practical level.
It would be a great base for you to learn how to work quickly and efficiently, what kind of things you would need in your own salon, what you like and dislike, booking systems, client management and quite a few quick fixes and trouble solving tips.
I know it can be difficult getting into a salon job, but i really would try if at all possible.
I started doing work experience, then i switched to a salon that wanted a receptionist and wanted to nurture me by letting me practice on the other therapists and watch their treatments, moved to part time work in the treatments i was qualified in and then full time, afterwhich i started renting a room on my own.
There were 28 girls that started when i did in two classes, 8 had dropped out by the time we finished first year and only a few of us still wanted to do beauty at the end of it all, so i wonder of you classmates will still want this later on.
I think you are doing really well to get all the information ahead of you before you get started and the hmrc courses for new, sole traders and business owners are free and a great start for you.
Good luck xx