It took a while for my mom to realize that I've grown up -- even after I got married, became a mom myself and got divorced. I was very resentful that I was being treated like a child even though I had graduated from college and was even a Director for a hospital. So, one day I just asked her to start treating me like a grown-up because I have already earned the recognition many years ago and that I deserved it.
I thought we would end up having a huge fight over it, but she just said, "okay."
I was surprised that it was so "effortless" to get her to admit my grown-up status. After a while, I realized that I was the one that needed to be convinced that I had grown up. Before that time, I was over-sensitive to being treated like a child because I still didn't feel like I was a grown-up. It took a while for me to get over those issues.
My belief is that once you're convinced that you're a grown-up, then you are one -- and it doesn't matter what anyone else thinks.