Hey! I took the TOEFL English test a couple years back and was also super nervous / worried that my stutter would have a negative impact on my score. The fact that you sat in the same room as the other people (thinking they’re all listening to you when you stutter) didn’t help. Anyways, I did really well in my oral section and was clearly judged by my vocabulary and not stuttering. I think I even quickly mentioned that I stutter when I answered the first question, so the person correcting knew. Good luck and practice your English, that’s what matters :-)