I was 53 when I changed from my job as a lecturer in a vocational
college in Hong Kong, teaching computing, electrical engineering and
systems administration for eleven years, to working as a hands-on
engineer doing plenty of interesting software development in a large
ISP in Australia. I have thrived since the change, and feel less
stressed, not having to mark so many assignments, and not having to
deal directly with plagiarism while hiding it from the administration,
who pretend that it does not exist.
I love my work still, more than five years later, and enjoy working
with free software; this allows me to produce solutions to problems
without requiring support from management, except for paying for my
labour.
I might add that although I am now close to 60 years old, I still ride
my bicycle 160 km each week, and have a lot of energy and enthusiasm.
Also the subjects I taught and wrote the teaching material and
practical laboratory exercises for apply very directly to what I do in
my work.
I feel very lucky. Please do not listen to all the negative comments
you see here, moderated as 'insightful'; if you have the enthusiasm,
go for it. You will feel sorry if you don't.