A teenager this morning admitted robbing a grocery store with an imitation firearm in May.OJ Campbell, 17, from Pembroke, pleaded guilty in the Supreme Court to charges of robbery and using an imitation firearm to commit an indictable offence on May 28.However he denied a charge of taking a motorcycle without consent on the same day.All of the offences were linked to an incident at the Rubis gas station on St John’s Road, Pembroke.Prosecutor Carrington Mahoney accepted the ple