I’m also not much help ( being outside the UK), but I am around your age and am currently studying for a degree. I actually went to uni in my late teens, but it proved too overwhelming and stressful for me. Returning as a mature age student has been something of a godsend in that respect. As Sparrowrose states, being a mature age students means that you don’t have to put up with the social crap that younger students are often subjected to. No-one will give a damn if you rarely ever communicate with any of your classmates, and spend your entire time studying.
Having said that, it hasn’t always been easy, particularly in terms of trying to manage doing multiple subjects, and the anxiety associated with studying. Almost all institutions have disability units set up to assist you, if you require accommodations.
I would definitely encourage you to give it a go.
I could well be wrong, but I would be very surprised if UK universities didn't have foundation courses for adults seeking to enter tertiary education (like they do here in Oz). They often involve you taking a limited number of uni subjects over six months or a year, basically so you can prove you are capable of undertaking an entire degree. The subjects you do are often then credited towards the degree. The good thing about these programs, is that they also give you the opportunity to decide whether study is what you wish to do, before handing over big sums of $$$.