It looks very made up and trashy too me. It just blends with all these -lyn names made up in an effort to be "unique". I personally don't like the "Shay" element either. Plus, I find it much too informal and cutesy. Children don't stay 5 years old forever. A 32 year old professional name Shaelyn or Shaeley is hard to take seriously to be honest.
Thumbs down for me.