1. It is about Tom's worries on his height and changes in teenagers' body and mind.

Question

2. It is about Tom's worries about his height and changes in teenagers' bodies and minds

3. It is about Tom's worries of his height and changes in teenagers' body and mind.

(Which one is grammatically correct? Would you let me know better expressions? Thank you.)

4. Girls grow a lot between 8 and 13.
5. Girls grow a lot between the age of
8 and the age of 13.
6. Girls grow a lot between the age of
8 and 13.
(Which one is correct?)

Answer 1

Of the first 3, only # 2 is correct.

4 and 5 are correct. You can also use 6, if you make age plural. "Girls grow a lot between the ages of 8 and 13.