@Spud88
NC so I can share openly as I might be recognisable.
Went to uni at 19 and studied music, it was the thing I loved and nothing else would let me in due to my poor grades (really tough teen years, lots of family strife and self harm etc.), Ended up working as a bank cashier on next to nothing. Volunteered since the age of nineteen consistently in various roles from the Samaritans to a prison rehab unit.
Ended up going back to university at 24 to study a MA in social work, graduated a qualified social worker. Absolutely beyond gruelling. Went bankrupt at 24 due to poor health meaning I wasn't able to get to work some days and ran out of sick pay. I was earning about £11k when I started and finished uni, the bursary was tiny and so I had to work eighty hours per week for the majority of the two years across different jobs to support myself on top of studying.
Qualified as a social worker, joined the NHS in a mental health role, they paid for further training to become a therapist. I'm now earning £40k in my mid thirties. £11k to £40k in ... five years, maybe six?
For me the key was to secure a professional registration in a job that pays well: nursing, social work, occupational health, teaching, any of those fields have a guaranteed starting salary and end up paying really well as time progresses as you remain in the job, just look at the top of band 5, where nurses start: after four years you're on over £30k. You have a reliable income which is harder to achieve imo with jobs and degrees that don't align with a profession. I didn't go down this path for money, it was always my passion (hence the volunteering for years before even starting to think about what to do for a living), but if I had to give advice to someone looking at uni courses it would be to strongly consider something that leads to a profession or a well paid job (engineer for example) rather than something a bit more artsy or vague, unless you're happy to take your degree and go into teaching.
The other side of the coin is to marry or have a relationship with someone on the same page. After a string of relationships with guys who were nowhere near financially secure enough to consider marriage or kids I made sure in my late twenties dating to only consider getting serious with someone who could match my own degree of professional success, I wasn't looking for riches or an incredibly high flying career but I didn't feel secure starting a family with someone on minimum wage as I know what a struggle that is. I just wanted to meet someone who could equal what I was bringing to the table. Met DH, he was a few years younger but in medical school. Graduated a year or two after we met as a doctor and he's doing great. Choose a partner wisely, money isn't everything but the financial habits and stability of your partner go a LONG way to setting the financial tone of your household together, it's a nightmare if you're with someone useless with money or pissing it up the wall (I say as a former bankrupt person), and it makes having kids that much more likely if you're with someone who knows how to earn well, manage money, and provide.
There's ALWAYS an element of luck involved, I was lucky enough to get onto my social work course the final year that offered everyone a bursary and the fees paid for (to encourage people into the profession), if I'd been a year later I couldn't have done it. I was lucky enough that when I lost my mum tragically it was a couple years before so I had a bit of time to grieve and it didn't affect my studies or work. I was lucky enough that my chronic pain had stabilised enough at that stage to be able to attend regularly. Sure, I would have loved to not have had to work eighty hours per week, it drove me into the ground, but the hard work I put in doesn't negate the luck that enabled me to make the most of the opportunities that crossed my path.
It all comes down to career/education choice and who you choose to share a life with imo.