You son of a ..... You did it . But on serious note , it's like what it is showed in the movie "she's put of your league" it's not if you are enough for her. Are you enough for you ? If you are comfortable in your skin I don't think it'll affect you but I'd you are so scared about it just go and tell her and talk to her about it . 99.9% she'll like the honesty and not care about the stutter