DD1 was supposed to have grommets in at 3, but the waiting list was too long & she was 5 when it was done.
The second they came out she started getting earaches & suffering hearing loss again. I took her straight to the gp, who gave her the usual abs to clear the fluid, but thats all he's willing to do at this stage. They won't look at grommets again unless she starts showing signs that its delaying her learning/speech etc. We just let the school know when there's a hearing problem, so she sits at the front & do the abs again.
But, my DD is 8. Her speech developement is very different to a 3 year olds, so things could be completely different for you guys.