Will they learn all they need to know?
Unschooling sounds good and seems to work as far as keeping my son happy with learning. But I'm having serious doubts that HE is learning all he will need later.
If we assume there's a body of learning that is unconnected to what it would be used for, then that's a legitimate worry.
Unfortunately school gives us the impression that there's a huge body of knowledge that's unconnected to its use. Mainly because schools teach it that way: isolated and out of context. It seems the only way to learn math is to do a gazillion math problems. The only way to learn science seems is to memorize all the answers scientists have discovered. The only way to learn history is to start at the beginning and go through all the "important" events to present day.
But when we learn by living life, all those subjects are just tools that we pick up and use when we need them. And we learn how to make the tools work by using them.
There's no reason not to use (and learn as a side effect) math when there are games and things to figure out and stuff to spend allowance on. There's no reason not to use science when the world is full of wondrous things and a child is filled with curiosity. (It won't look like school science. It will look like -- and be -- real science: observing and asking questions and theorizing what could be the cause.) There's no reason not to use history when the past is full of stories of interesting people and places and events.
I'm wondering if I truly trust my daughter to learn what she "needs" to.
Perhaps if you word it as "learn what she needs to" it will help. I think if you're checking scopes and sequences, you're expecting her to learn all that on her own. What she needs to learn are the skills and knowledge to pursue the things that interest her.
But I wonder how we are preparing them for adulthood then?
How did you prepare your newborn to be a toddler? How did you prepare your toddler to be a 6 yo?
They learn what they need now. The nows just naturally keep coming along and the kids end up where they are today already knowing what they needed last year and acquiring what they need for today.