Is it some kind of disorder??

If she is still attending public school from K-12, either you or her parents can refer her to the school counselor or school psychologist. You should write down a description of her behaviors that concern you just like you did here at SW. For schools to regard this as a genuine problem they have to see that her behaviors are consistent over a period time and that they have resulted in effecting some area of development such as in academics or ability to form social relationships. Many public and private schools have "communication social groups" where the shy and anxious meet to practice skills that will help them overcome their fears and get back into the swim of the school social network.

Good luck to you! Your cousin is blessed to have such a caring relative.

I used to be like that. I didn't talk for 24 hours at a time, not even 1 word for days. Not even to my family. It was because I was abused at home and bullied at school. Gave me really bad social anxiety & anxiety in general. I always looked at the ground when I walked & never made eye contact

I've had those issues when I become really reclusive. Generally, my thinking was that I didn't care about those people, so they were a waste of my time. So I avoided as much contact as possible.

Maaaybeeee...it's some type/level of autism?

@Popobandar
You're right to look for professional assistance when it comes to mental health issues. They are complex and can have some bad effects if not treated. If a school counselor is not available to your then see if your town has a "Community Mental Health" system. Get an appointment to discuss your concerns.

Mental health is too important an issue to leave it in the hands of people who are not experts or just getting responses here at SW.

Not everything is a disorder.