...It's something I've always wanted to do, so I'm sure it can work...
It's you who will decide if it will work. You will decide about that every day.
If you work 40 hours now, stop that, and put 40 hours a week in studying, you will get a AA++superplus grade.
...a little worried about the maths though.
If you understand (Or once-undestood, or potentially-understand,...) this for example :
http://en.wikipedia.org/wiki/Quadratic_equationMeans your brain is developed enough, healthy and ready for the rest of the math.
Don't look at what the math looks that you will need in 1 year, it looks nasty, ugly and spaghetti.
It comes in layers, every layer is explained, excercised, between other people who give time and courage to understand it.
The most difficult is to DECIDE to START. If you're afraid: Do it for 5 months, decide after the 5 months if you continue or not.
Do it. Don't be afraid of 5 months.