How to generate random int around specific mean?
Yes, there is. It is random.triangular(min, max, av). 
Your mean value will be close, but not equal to av.
Edit: see comments below, this has drawbacks.
I need to generate 100 age values between 23 and 72 and the mean value must be 42 years. 
Do you think such a function already exists in standard python? If not, I think I know python just enough and should be able to code the algorithm but I am hoping something is already there for use. Any hints?