AJ -- you seriously think a brain can function and absorb as a senior versus a child? Do you have any proof of that? I just find that amazing and I would hope to think so.
I'm a bit older than you. There is no proof the other way around either. I'll suggest that we are individuals with individual differences. Chances are that when we were both in our twenties, that the differences were there too. The biggest obstacle in age is the tendency to do things how you are used to doing them, and comparing everything new to something that is familiar. These are habits, and habits can be changed once you are aware of them.