it sounds ok to me !! have you got it on firm enough?? as long as her legs are under the black straps and you have it on right , it should be save , if she is tall then her head will pop up further ..

do you have the infant insert ?? is that what you mean by tucking her head under ??

do you think she is safe ?? if in doubt , put it on again and keep doing it till YOU feel she is safe !!

hope babe feels better soon !!