You could have her tested by a psychologist with the WPPSI-III or SB-5. That may give you an idea of where you stand.
My DS started reading at age 2 1/2. We decided to have him tested at age 4 1/2 to get a better idea of his level of giftedness and to get recommendations from the psychologist about appropriate school placement.
Even if private school is too expensive, you may be able to enroll in a distance learning program like Calvert Homeschool. It's not free, but it's a lot cheaper than a private school! You could work with her at home until she is old enough to attend school and worry about appropriate placement then.
