Yeah man go apply for that position, it seems like your managers really like you if they told you that. And with your coworker, I agree with what the other OP said, she’s definitely using a defense mechanism to make herself feel better there. I feel like the main reason people will mock a stutter/use it against you is only if they feel uncertain or insecure about their situation in their own lives. For example my friends usually never make fun of my stutter. However, often times when we’re together in big social situations or around girls, that will often mock my stutter when I talk. This is because they feel insecure about themselves here, and use my stutter as a safety blanket to reduce some of their insecurity. Honestly I’ve learned that you can’t control other people, only yourself. Us stutterers are mentally stronger than most people out there because of all the things we have to go through. Go apply to that position bro, who cares what that girl thinks.