I went to a CT private school from pre-K through 4th grade and it set me up well in reading and foreign language but I was behind in math when I transferred to public school for 5th grade. I stayed in public school through the end of high school and ended up at a top tier university for college. My parents stayed in touch with my former private school classmates’ parents and most of them turned out fine but few of them ended up at Ivy+ universities, most were at other high-ranking universities though. Post-college, we’ve all had similar, respectable outcomes in different career fields. I think all of the schools in CT are pretty strong whether they are public or private.