M.H.
My son sucked his thumb and totally stopped on his own a little after his second birthday. I never said a work about it. My mother-in-law always told me we should do something about it and I never thought it was a big deal. I think she can do it for awhile without you being worried. The teeth thing takes much longer to kick in, I wouldn't worry about it yet. With my son, if I talked about it and made a big deal, I'm sure he would still be sucking on it just to do it!!