This sounds a lot like my own experiences growing up. We started homeschooling when I was in 3rd grade, and I used Saxon math. When I reached highschool, in nearly all my subjects I had weekly classes taught by other parents with specific domain knowledge, with other students---anywhere from 3 to 10 or so per class. We had ten of us in chemistry, and 16 or so in biology, both with labs. For physics and calculus I found a tutor, a local homeschooling dad who was an electrical engineering university professor, and I had a local Anglican pastor as my Greek tutor.
I found that a solid elementary school foundation from my parents, combined with weekly classes and individual tutoring during highschool, was excellent preparation for my university studies.