Adoption regrets?

Thank you so much for all the helpful insights. I have to say that it's not really my age that makes me have doubts. I know a few parents my age that also have small kids. The issue I have is that I'm not sure if I want to start over again. I've been a parent for 24 years and my hubby and I were looking forward to having some time to ourselves. Of course, that all means nothing when you are living with a child that is such a part of your family and you can't imagine life without her.