I completely get this. Typically I’d arrive early with the intent of now actually showing up. I’d just chill or walk around until it was like the “perfect time”

I had this too growing up! I think adhd people either hate being late or are late all the time. I grew up hating being late but then I was in a job where time constraints were hard to meet and I was late all the time and then now I’m late for everything g haha

I think breathing exercises helped me. Also, thinking through things. If I remind myself that it’s okay to be nervous but it’s not going to have a big impact on my life has helped. Idk if that helps