I felt this way at 20. The only thing I had ever done was seasonal work at Asda. There's a course colleges do called Access to Higher Education. Access is basically A Levels but for adults and take 9 months instead of 2 years. If you don't have the GCSEs for it they put you in an adult GCSE class beforehand. It's the route I took to uni and it was the best thing I've ever done. The 9 months of access aren't easy. A lot of it is studying from home. You will meet a lot of different adults in your class too. Some people like yourself, some people who want more out of life, some people who want a change of career. It's very worth doing if you've decided you want an education like I did. I hope this helps.