it really depends on you , in MMA you should be well rounded but if this is going to be your first foray into any type of martial art. Then pick something you know you'd love to do day in and day out. For example I don't like wrestling /grappling/using submissions/ throwing people around. But i do love to throw hands knees and elbows with a person. So I'v picked Muay Thai as my martial art and i'm loving every second of it.
Just pick something that suits your needs/wants.
" Keep away from those who try to belittle your ambitions. Small people always do that, but the really great make you believe that you too can become great." ~ Mark Twain