I would agree that you should focus on developing for a single platform until you have a good solid product out there. However many a developer that does this after the fact realizes how much effort and additional cost is then needed to completely rewrite the game on a new platform. Would a little upfront thought you can minimize the need for rework and thus minimize your cost once you are ready to port your game. Android is too big of a market share to completely ignore it; in my mind Cocos2d-x is the way to go if you like Cocos2d.
