Uni Help...?

I am nearly 15 and for the last four years I have had my heart set on studying child psychology at St Andrews university in Scotland, however I live in the south and it would mean staying on campus, yet my mums a single parent and we are only just about coping with funds at the moment. I work whenever possible to save for it but we are not entitled to any grants because we dont live in scotland. im planning to take a gap year to work and try and get enough money for my first year and then work while im up there but how am I going to afford accomodation, living expenses, course fees etc. please dont say im too young to be thinking about this because its only a few years away and I need to start thinking about it now to raise enough money… but how can I possibly get enough to go? x