That was me a few years ago, (I'm 23 now). What was meant to be a 3 year degree dragged out over about 4-5 yrs, and I ended up failing the last semester. When I started it, I naively thought it would be a good investment and lead to a well paid job. But my degree is still not finished. And I want a baby now more than ever.
So I am getting a job and working to earn money to move out of home. After 2.75 years completed out of a 3 year degree I have now deffered. My degree was not a good financial decision at all.... It has been such a struggle financially and mentally. The work just got harder and harder, as my motivation got lower and lower.
Even now after all my study, my degree works against me as lots of employers think I will not stick at any low paying/repetitive/boring jobs as they think i will be too ambitious and leave after a while. But the better paying jobs won't take me as I have not actually finished my degree yet, I am not a graduate. I really regret going and feel really foolish and depressed about it. My advice to anyone thinking of doing a degree or just starting a degree is to only do it if you REALLY enjoy it, and you KNOW you want to use it for a specific career path. Otherwise get out ASAP.
You sound like you would like to be a youngish mum, so why do such a long degree? IMO uni is really designed for women who plan on ttc in their 30's. Othwise you should think long and hard about wether you really want to do to this degree? In Australia we have TAFE, which is basically a shorter, more practical, less expensive form of uni. With lots of short courses you can do which directly help with employment. I am sure they would have courses like that in the UK as well.
