I think I've done a decent job of teaching her at home, but I also wonder perhaps if I'm failing her bit, and slowing her down.
I think by all means you should look for a teacher, but I wouldn't rush into it. You need a teacher who's experienced with VERY young students, and that may not be easy to find. At that age every year makes a big difference -- a 3 year old would have to be taught differently from a 4 year old, which is different from 5, etc.
Slobone - I know it sounds strange that her fingers are strong enough to play at that age, but she plays chords with her left hand while playing with her right hand, so I think her fingers are strong enough. Here's a video of her at 3 years and 5 months...