I went back to school as a grown up and tho I'm not the best student in the world I'm good with the getting going bit!!
Do you have any idea what you want to study or are you looking for inspiration?
Depending on your chosen study area most colleges now offer something akin to an access course for mature students (around a years worth of study at 16 hr pw - though a biology/chemistry/physics route may be 2 years..)
Access courses are really useful for things like learning to structure assignments, exams ect.. and usually contain refresher gcse's (or equiv) in both maths and English as part of the course. Plus you will gain enough equiv a levels to get you onto most university courses as an adult learner..
Alternatively some universities offer a foundation year (course dependent) however these are usually open to all ages so expect students from 18+ on these..
PM me if you want to me to go into detail otherwise I'll bore half of Blonde to death
GL whatever you decide
xx