Is it signs that I should be concerned about in my 17 month old granddaughter

There’s a few things that my granddaughter is doing which has alarm bells ringing.

The first thing was a head shudder at about 12 months old not all the time just an occasional thing. 

Secondly she covers her ears at certain noises and sometimes when people she doesn’t see to often talk to her. 

Thirdly she eats Everything! And love sand, crayons,pencils, toilet paper, stones etc. 

She is only 17 months and I know I’ll be told it’s all normal for her  stage of development and like wise it maybe but I’m a nursery nurse in education with a good understanding of child development and I’m just not sure. 

She makes eye contact, interacts with us and others and is saying about 6 words. I don’t have concerns generally about her development but something just keeps niggling at me. 

Any advise would be great 

thank you Blush