I Don't Wanna Grow Up

As I'm getting older and realizing that my life is a series of challenges and obstacles, I see that there's not really a place when I get to step back and say, "I made it!" Well not until I'm dead I guess. But the reality is that my body is getting older, but inside I still have the same insecurities and questions. They may be in reference to different things, but they're still there.
I guess that I thought that by the time I was almost forty, I would have a certain confidence from life lived and experience gained. But I doubt myself all the time. I ask questions like, "Is this what God really had in mind when He called me to Himself?" or "Am I really being the best mother to these children, and wife to this husband?" Is this what I've worked for and waited for and prayed for? Or is it still somewhere out there illusive and shadowed by doubts?
Does anyone else in the world feel this way? I mean I thought that there was a point when you grew up and accepted your life and were happy and successful and could sit around enjoying things. Does the hard work ever get easier? Does what other people think ever shrink in its importance to you? Do you ever look in the mirror and like what you see?