This happened to me Whizzylala.
I learned to read at 2 (dm was a primary teacher, I was interedsted), could write soon after.
When I started Infant school, I had already completed the infant 1 reading scheme, so they put me directly into the infant 2 class.
As they thought it would cause problems later, I had to repeat infant 3, though in a different teacher's class.
It was horrific- I can still remember being heartbroken in the playground on the last day of school, when I realised all my friends were going up to juniors (separate building) and I would have to stay back.
I was bored the whole year I repeated (though thankfully I had a lovely teacher, much nicer than the other infant 3 teacher, who I had hated). I never really made proper friends in my own age group.
I was also way ahead of all my classmates throughout junior school, which was a horrible, and boring experience. I learned more in the first 2 years of school than I did in the next 5.
At secondary, I went to a different school than all of my classmates, so it didn't make a difference there, but I had already been turned off school by then.
If you can stick with the independent, I would say do it.