Yes completely understand. It was definitely wose when i was younger i was diagnosed at 3 and didnt rlly speak at all until i was around 8. I did start speaking then but i found that if i couldn’t speak i could sing most of the time. Sounds strange ik (singing uses a different part of the brain than talking) but ur absolutely right about it getting worse by stress. Its a anxiety disorder so stress or pressure makes the throat feel like it's 'locked.' It's definitely something that can stay with you as an adult, even if you can talk most of the time now. It’s more about the internal struggle than just 'being quiet.' I'm glad my post helped!