There's really no way around it. No matter how horizontal you go, she's going to learn skills that will advance her up the academic ladder. If she learns a language, she'll also be learning about spelling and root words and sentence structure that will apply to her writing skills. If you learn about the history of measuring devices or some such thing, she's going to figure out conversions, for example. So while I think it's great to be able to take the opportunity to teach deeper and more off-the-ladder topics, I think there's absolutely no way that she won't learn school stuff. Nor do I think there's anything wrong with that. IMO I think you're right that all you can do is follow her lead. She's a new little soul, smart as she is, and she loves learning about her world, and that's an amazing thing. Don't let anyone tell you otherwise.
I know it's really necessary to try to get a handle on things and try to figure out what you're going to do academically now, next year, 5 years down the road. I'm personally a huge planner and I like to have all my ducks in a row, but you're really only going to be able to have control over a few months at a time. Add to that that you only have so much control over what a school system can/will do.
Luckily, you have advantages that the experts and the schools don't: you love your daughter, want only the best for your daughter, and live with your daughter and know her better than anyone else in the world does. She is still the same little girl that she was a few days ago and you've been doing a darn good job of meeting her needs thus far. (Which is not to say that I don't get that you're focusing on this right now. You're allowed to freak out on occasion. Not that I think you're freaking out -- I think you're having a perfectly reasonable response!)
With time you will figure out what combination of things at home and things at school and things in the community will work. And if you don't, you DD will!