I'm late thirties, and I'm writing code every day and fully intend to keep doing so until someone pries my ergonomic keyboard from my cold dead hands.

Something to keep in mind is that this industry is aging and maturing alongside us. You can't use historical precedent for understanding unprecedented events.

My personal hope is that the software developer monoculture (young dudes with ancestors in Europe or some parts of Asia) will mature into the kind of diverse profession where people aren't any more surprised by a female coder than they would be by a female orthodontist.