In my time working at retail banking as a personal banker in London it was my experience that most people getting mortgages were NOT 25 or under. It was mostly people in the 30 plus range. In this group I include people buying their first starter homes.

Of the people who did get mortgages early (people in their 20s) they often go a lot of support from their parents on the deposit. In fact it is often said that when it comes to mortgages one of the biggest providers in the UK is the bank of "mum and dad". In other words the reason get ahead isn't so much about being entrepreneurial spirit but just picking the right parents at birth. Any person who had no support and still managed to make a purchase in their 20s usually had a good story on how they got their wealth so quickly. But those were the exceptional people and were not the norm.

Whilst my experiences are from London I don't think there is a reason to believe these experiences are atypical and I bet a similar dynamic would be found in California.

We hear about the stories of the young kids getting mortgages because the stories are exceptional and news worthy. But they are the exceptions and not the norm. The reality is less people are able to afford buying a house with or without a mortgage and this is an indicator that there is a decline in the middle class. Buying a house is a middle class activity, you don't see the working class do it as often.

EDIT

Just found this timely article on The Guardian which describes the hotel of "mum and dad" (new term to me) being busier than ever before. The hotel of mum and dad is alluding to the fact that a fifth 24-34 year olds in Britain are living with their parents so you see mum and dad are increasingly taking on the roles of banking and hotels for these children and society in general:

https://www.theguardian.com/society/2025/jan/11/hotel-of-mum-and-dad-in-uk-at-its-fullest-in-two-decades-study-finds

It is a sign of our times this is happening and to simply blame it on the youth today being lazy is ironically a lazy response that fails to consider the prevailing economic conditions we live in.