Since you're still in school (high school, I'm assuming?), I really doubt that she has a clue what stuttering is. So, I think you should be an advocate for yourself. Even if it was supposed to be a harmless joke, it was not appropriate and was incredibly rude. If she thinks you're being too sensitive about a speech disorder then, once again, you should consider dropping her as a friend/relationship because she's not a very understanding person. You should bring it up to people. Remember that there's a good chance you're the only person they've ever met who stutters and because of that, they probably don't know anything about it. How I deal with it is I don't bring it up until I have a noticeable stutter. This could happen the first time we speak, or it could happen weeks later. After I stutter, I can gauge their reaction to see if they're not sure what just happened. If they look surprised/weirded out, I'll just say something like, "as you can probably tell, I stutter." This is especially good to say if they just made a joke about forgetting your name (or what your friend did) because they look horrified that they just made fun of you. But as you get older, you'll start to meet more mature people who can just tell what's going on and you won't need to bring it up. You'll be able to tell they know you stutter and it's very relieving. One more thing, you didn't fail talking to a girl. You had the courage to talk to a girl you like which is something fluent people have a problem doing. She is the one who failed by being a jerk. Hope this helps.