A few short answers:
Age legislation means CC can now work as long as they are fit and able to perform their duties. Flight crew hold a license and this is only valid until the age of 65, so all flight crew must retire at 65.
In terms of flying, it depends what you mean. We 'fly' the whole sector, however manually flying may be the first 3 minutes and the last couple. Take off's are always manual, landings can be done automatically in fog etc.
However, the computer may handle the controls but they are only as good as the inputs we put in. Route changes, height changes, fuel management, radio calls, weather avoidance etc all require the pilot to act. The automatics purely do what we ask them to do and allow us the capacity to do other tasks.
Turbulence is either 'clear air' or associated with clouds/precipitation. It is often associated with jet streams which tend to be stronger in winter.
Cloud turbulence is often avoided using the weather radar but is not always possible to avoid completely. Places in the world well known for large areas of Cb clouds are northern Brazil, sub saharan Africa and the Bay of Bengal.
It is sometimes very uncomfortable but aircraft are built to withstand strains far in excess of this. The biggest danger is not being strapped in to your seat and being thrown about or something falling and hitting you.
And once again, please, it's flight CREW. Flight deck is a place.