Playmates his own age.

The psychological inhibitions brought forward from youth may have prevented Peter from exposing his fragile ego to the physical intimacy of lovemaking. Peter’s childhood and youth had been horrendous. He had grown up an orphan in the unloving care of martinet tutors. He had been barred from having companions and playmates his own age.

Is it wrong if I add 'of' to the phrase in blue? I mean- ... playmatees of his own age? Thanks!