Wow. I never imagined low oxygen level affected stammering. Can you get a little pulse-ox finger metering device to monitor the ox level? They’re relatively inexpensive on Amazon or maybe your drugstore. About joining groups. You said there is limited opportunity at school. Have you considered joining a group of young people in your religion? If you’re not religious there are groups of people who have no belief. There is an international stuttering group in India that meets in person. Google stuttering groups and when you find them specify ‘India’. In the past I have referred stutterers, even women who stutter, to a group in India. I know this exists. Through those people you could connect with other, even local groups.