I would say its up to you where you want to start and what direction you want to go?however I would recommend both as you will want to incorporate rock licks in your blues playing etc. blues is a great place to start to get some good rhythm down and one great thing about the blue is most players find one or two really great licks and build a full career upon them i.e.. BB King , Eric Clapton , Buddy Guy etc......hope this helps:)