You'll be fine Meg10. Admittedly it is very daunting at first, after all the doubts, but once you're settled you'll realise it's probably the best decision you ever made. I went back to education 15 years after leaving school, where I basically messed about and didn't try very hard. I had a partner and baby and gave up a full time job to do an access course. I am now three years into a four-year degree where I'm training to be a dietitian and I love it. I would never have forseen myself doing anything like this, but I'm so glad I took the chance and went for it.
Good luck x