Growing, Growing, Grown!

So another friend of mine from high school got engaged the other day, bringing the precentage of my friends that are single down to 2%. I am very happy for her, her fiance is a wonderful guy and is so good for her. But again, I turn everything around to self-analysis (I will analyze why I do this later, I assure you) and so I wonder: When do we become 'grown-ups' and why does it seem to be so drastically different for each person? Studies have shown that most Americans view the age of being a 'grown-up' to be right around 25, but I am confident that I have met people significantly older than 25 that are hardly grown-ups, and I have met those that are 40 year-olds trapped in 16-year-old bodies. Maybe its that saying about having an 'old-soul'; that physical maturity and emotional/spiritual/psychological maturity are mutually exclusive (to an extent).
But what defines what maturity is anyhow? Webster's claims maturity is the act of being "complete in natural growth; ripe; fully developed." That doesn't really do much to help the dilemma now does it? Dang. Well I guess my conclusion is I may be mature psychologically and almost mature physically, but lawd knows emotionally I am a larvae. I'm ok being a larvae. I'm beginning to be at peace in knowing that though physically my friends and I may be the same maturity, we have been graced with rather different timelines at which our emotional and spiritual growths may plateau. It is for different and sublime reasons that our seasons of growth may wax or wain, and it is our charge, in our oncoming maturity, to understand that growth does not stop with maturity: it merely morphs.
Like a larvae.