I think the community college path is a really good one to consider, especially if you're looking for more rigor than high school. Being able to work with a professor and get pushed by them can be a great intellectual experience. Like PlantMom said, it's a great way to do more advanced work, which it sounds like you want.
But really, don't overlook those English and history courses! They're so important, especially English. You might be surprised by how much you get out of them.