It just feels like you gradually "give up" a life that was once yours (less responsibilities) and are "slowly forced" into a life that isn't as much yours (get married, buy a house, have children).

Doesn't "slowly forced" imply lack of agency?

> sense of agency refers to the feeling of control over actions and their consequences.

You're damned if you do (give up control) damned if you don't (walk through life unmarried with no kids in an apartment wondering what could've been)