Labels like "adult", and "successful" etc are all for other peoples benefit rather than our own. It's all a facade.

I'd probably measure maturity in terms of how one navigates relationships.

When it comes to my partner, being vulnerable, knowing when it's ok to share that I don't feel like an adult, that i'm scared or lack confidence, and when to put on a strong front and say it's all going to be ok, to make her feel safe, is the essence of what I consider to be a "grown ass man".

But we're also planning a trip to the Lego House, Denmark together and we don't have kids. So there's that.