A comment my uncle made

I'd agree. Until you're paying you're own way, you're not an adult.

There's a difference between being a legal adult and being capable of taking full adult responsibility for one's safety and care, etc. So I see where he's coming from. You really can't know what it's like until you do it.

However, living at home regardless of age may have nothing to with capability and generally has everything to do with financial security, particularly a lack of it. So making the choice to stay at home for this reason is pretty adult. A lot of people live out of home and, at some point, move back for a while for such reasons. It's a lesson you generally only experience as an adult.

Probably mostly but not necessarily always. Are the Trump kids not adults because whether they are living at home or not they are never on their own because of their rich father.