Sometimes things that make a younger child appear "young" are due to poor developmental fit with age peers, not immaturity. My dd12, for instance, cried not infrequently in 1st grade. She held things in in K, but came home deeply upset with the other kids and sometimes the teacher. She was insistent with me that the teacher assigned her a specific topic for a writing assignment b/c she (dd) is vegetarian and the teacher was trying to give her an assignment that conflicted with her values.

She alienated other kids in 2nd grade by incessently harping on environmental and global concerns and insisting that they circulate petitions for trash cans on the playground and spend every recess picking up trash. She held grudges -- I recall one girl who dd wouldn't speak with b/c she had made some comment to dd two years prior that had offended her.

In any case, she started K shortly before her 5th bd and it was definitely the right decision. She also skipped 5th grade and that was also definitely the right decision. In hindsight, I think that both 3rd and 4th grade would have been better fits if she had skipped sooner. She was, and is, intense and sensitive, but she is more developmentally similar to older kids and they are much better peers for her.

What types of concerns do you have regarding your dd and placing her with older kids?