You shouldn't feel like an "old fart" using Django or Flask. I think both are awesome, relevant, and will stick around into the future.

One of the great things about being a programmer is that we know how to program in general. If we have to adopt a new syntax or learn the intricacies of some new methods that's ok, and not nearly equal to the amount of effort we expended to learn how to write code in the beginning.

Keep writing your Django apps. I agree that it's great that DSF is backing a stable and productive framework like Django.