I also try not to write too much fingerings asap.
However, it is true that not all kids can read the score quickly.
I am glad that my daughter needn't any hints in fingerings at all. :) Perhaps I taught her to read the score when she was 3. I didn't ask her to play formally at that time.
but i prefer not label the fingering on the notes as sooner or later the kids will just read the fingering and ignore the notes... I will even cross-out the fingering when i teach them to read the notes.
:)