'All grown up and doing the town'?

Can any native English speaker and movie fan inform me about this expression: "all grown up and doing the town"?

I found this expression in "Goodfellas" movie but I didn't understand its real meaning.

Thanks in advance


doing the town is an idiom that means going to lots of fun places in the city like bars and nightclubs. These generally only admit adults, and all grown up means having become an adult, so the people discussed are able to do the town.