If you doctor is saying no, and from everything you have stated, she's just shy, it could also be the age.
Children when they first start pre school and even into kindergarden, they feel a little overwhelmed by it all, all the different children the new adults, a new area they really aren't used to ! But as she advances in age, she will either grow out of it, or when she starts to make friend's she will feel more secure in her school !
Her motor skills, your doctor will know best, XXXXX XXXXX its age as she grows she will improve. Her way of speaking and doing projects, that will all change.
During the summer practice with her so she keeps colors, numbers, words, etc. in her memory. Give her regular projects to do. The library is a great place to help during the summer. They have many different programs to keep the children interested and to keep their little minds active and busy !
Just take it a step at a time and encourage her, work on projects with her and make it a fun time ! I believe you will be surprised at how fast she will soon be !
And if she is the little chatterbox at home, she will be when she feels secure, keep helping and talking to her she will get over the major shyness after awhile !
If you have any other questions or concerns, I will be here !