Someone who doens't want to date you because of your stutter is someone you don't want to date anyway. Just go for it, if that's her reason for turning you down she's doing you a favor. I know that sounds like cliche advice but it's true. I was a lot like you in the past and the whole "be friends first" thing doesn't help or work. Just go for it, and be fine with moving on if she says no. There are plenty of women out there that don't care at all if you stutter or not.