This answer is not correct. You have attacked the methyl group of the nitrile, replacing a hydrogen atom with the Grignard reagent. Hydrogen atoms are really bad leaving groups. You then hydrolyzed the nitrile to the carboxylic acid...remember that this reaction needs both heat and acid. The alkyl group of the Grignard reagent is for all intents and purposes a carbanion and will readily attack electropositive sites. The carbon atom of the cyano group has less electronegativity than the nitrogen atom and thus will be electropositive. Try working out a mechanism and see what happens.