1. I'm worried about my new school.

Question

Why don't you join a club?
Why don't you make new friends?
Why don't you talk with your homeroom teacher?
Why don't you talk with the school counselor?
Why don't you talk with the counseling teacher?
---------
Are they all right? At the bottom, are both expressions OK?
=============

2. I'm worried about my math.
3. I'm worried about math.

4. I'm worried about my height.
5. I'm worried about height.
---------------------
Do we have to add 'my'? If we don't use 'my,' does it have any difference?

Answer 1

1 - all are good.
2 & 3 - You might better say, "I'm worried about my math skills." #3 is fine as is. Both do mean the same thing, really.
4 & 5 - If you are worried about how tall you are, #4 is good. If you are worried about climbing too high, #5 is good. They do not mean the same thing.