Those darn vowels. There aren't alot of nouns that start with them.
I like the insect idea. There should be alot of those around.
I'm sure these were already said but indian, ice cream (she'd be a hit), indigo (a color, I'm sure you have a crayon in indigo), ivory (color, since I doubt you have any ivory laying around), iris, invention (make something up..........sh
e's 5 she'll get away with it.........lol), illegitimate child........o
h wait, that probably wouldn't work
, irreplaceable item (better hope she doesn't break it)