Sorry but which science fantasy novel or historical novel have you been reading. Your comments are so far off the mark.
I was born in 64, I had a savings account at 4 in my name. I had a current account at 16, I got my first mortgage at 21 in my name only, and my boyfriend lived with me...openly, quite normally.
Women have been able to have bank accounts in their sole name in the UK for a few hundred years.
It is however true to say that my mums generation of working class, could not get mortgages in their own name without a male guarantor until 1975.
Also, just for a bit of content, kids left school earlier and were expected to grow up quicker then too. People born before the early 1930s could often leave at 14 so had 6 years of "adulthood" under their belt before they hit 20. You didn't get kept for free by your parents, you were expected to hand over your weekly wage and they gave you some pocket money if you were lucky.
Those reaching school-leaving age from 1947 onwards had to stay until 15, and those affected by the 1972 reform had to stay until 16. It wasn't normal (well for working class kids) to stay on to the 6th form, let alone go to Uni.
My siblings were the first in our extended family to stay on for A levels, let alone go to Uni. I did Uni in my 40's! But our experience of relationships was the same.
In the UK, people began marrying later mainly because the milestones that traditionally came before marriage started happening later, and because marriage itself became less essential. Some of the biggest reasons were:
Longer education: More people stay in education into their early 20s and beyond, delaying full-time careers and family formation.
Housing and financial pressures: Buying a home, saving for a wedding, and achieving financial security generally take longer than they did for previous generations.
Women's changing roles: Since the 1960s and 1970s, many more women have pursued higher education and careers, reducing the expectation that marriage should happen soon after leaving school.
Less social pressure: Earlier generations often faced strong social expectations to marry before living together or having children. Those expectations have weakened considerably.
Acceptance of cohabitation: Couples can live together without marrying and face far less stigma than in the past. For many, marriage becomes a choice rather than a prerequisite.
Changing attitudes to relationships: People increasingly prioritise finding the "right" partner, personal development, travel, and career goals before settling down.
The statistics reflect this shift. In England and Wales, the median age at marriage for opposite-sex couples reached 34.8 for men and 33.0 for women in 2023, among the highest ages ever recorded.
Historically, marrying young made more sense because people left education earlier, secure employment was often available in the late teens, housing was relatively more affordable. There was strong pressure to marry before having children or setting up home together. For example, it wasn't unusual for British women in the 1950s and early 1960s to marry in their early 20s, whereas today first marriages are much more likely to happen in people's 30s.