art foundation at 21?Watch
Student life, in partnership with UEA
One thing to note is you will need to pay fees for a standalone art foundation (FAD course) if you are over the age of 19; you might be able to get an Advanced Learner Loan for this though.
If it's a foundation year integrated into the degree programme then the above point on funding doesn't apply. Also in that case there will probably be a more diverse range of ages represented as well.