Precisely this. For all the (woefully young) science about brain development and maturity, it doesn't seem to stop for quite a while, and my late 20's and early 30's have been the most interesting time of reflection and self-appraisement I've had.

It's becoming clear to me that what we call a "mid-life crisis" is probably just Jung's self-actualization, where a person becomes aware they've been wearing a mask to some degree until then. It seems most people find a way to drop it, stop doing what they don't want, and start doing what they do want. Hence the development of grumpiness, divorces, moving far afield, buying sports cars, becoming ascetics, whatever it is that reflects a truer identity than their young selves that satisfied expectations and chased approval.

I've found that the people I know who naturally reject molds and masks while young and pursue what they want early on don't seem to go through this.