What size Neverfull is this?

Definately the MM. I'm 5'3" and it's fine for my size. The GM is huge and definately is not an "everyday" bag unless you carry the kitchen sink with you! I would use the GM for more of a traveling tote bag.
 
That is the MM. You can tell because on the GM, the ponchette won't touch the bottom.

I have the GM and I love it because we use it for when we go out shopping, etc. For a purse though MM is the right size.