I used to be this way. I've gotten in a few alterations, but mainly when I waa younger (about your age). As I got older I grew more comfortable with myself and my stutter. I would still call people out, but not very aggressively. Nowadays I'll still speak up and defend myself, respectfully but firmly. Most people are super apologetic, some seem offended I asked them what was so funny in such a way. Sometimes I just give a dirty look. You're not in the wrong on defending yourself and not putting up with mockery in any form. I very much believe that: It's not what you say, it's how you say it. You can show intolerance without showing aggression. There's no real need for it and it's not worth it.