This one thing the OP is describing doesn't sound serious by itself. There could be other things that along with this indicate there is a problem. Without knowing more (and having never met the child) it's hard to say.
Yea that doesn't sound serious. My niece is autistic. She doesn't talk at all. Your child may just be shy that's all.
I would talk to her teacher about ways to get her to join in on the fun with the other children. Can you invite over one child she likes the most for a play date? It really helped my daughter in preschool to make friends with one girl outside of school. Many children with autism are antis-social, but just because your daughter has one symptom does not mean she has autism. If you have concerns the best person to speak to is her pediatrician. How much time does she spend at preschool?
Hi!
This does not appear to a situation to be really worried about. Many children are shy in the public. You could assess your child’s strength and let her school teacher know about them. Gentle coaxing, performing and being encouraged to do activities she likes will bring her out. Praising her attempt will be an additional motivating factor. Also you can talk to her school counselor regarding this. Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.