There has always been some question among Shakespeare scholars about the exact age of Hamlet at the time of the play. Some believe he was a young lad of 19 while others maintain he was the mature age of 30.In fact, this is one of the subjects broached early on in Theresa Rebeck’s play “Bernhardt/Hamlet,” under the direction of Donna Feore, currently running at Goodman Theatre, 170 N. Dearborn St., through …