The question is if that has gotten better over time? Because age doesn’t really change all that much in my experience.
I believe generally most people do grow and mature over time. Sometimes it's not that obvious externally or even internally without reflection, but it's a natural part of aging IMHO.
My Wifes parents on the other hand might not have grown up but on the other hand they would have divorced way sooner without a child forcing them to stay together
My Wife comes from a country where getting married and having kids before the age of 20 was very much the norm at the time, which led to a lot of people having children at a time where they were not ready for that responsibility.