R.J.
A thousand years ago, long before there was a "term" for it... my mum "afterschooled" us.
At least 90% of what I know, how I learned to learn, I learned from my mother.
Back then, school was only 5 or 6 hours long. We were home by 1 or 2 pm, and then the afternoons and evenings were hers. What we did didn't look like school. There were no worksheets, lessons, papers, or set aside time. We read (actually dodging books winged at us from time to time, and that's not a metaphor), we travelled, we explored, we went on field trips, had dinner parties full of interesting people, were signed up for outside classes/activities, we TALKED; in the car, at the table, on the living room rug, in lines, on bleachers and beds, in tents and libraries, on pool decks and hiking trails.
Excluding 4 years (2 separate 2 year stints... we moved every 2 years) I learned nothing in school that I hadn't already learned from my mother in greater depth and detail until I got to college. Even then, I've taken courses that I learned at her knee.
I'd planned on doing the same thing with my son, with a fairly minor/major tweak (I'd planned on homeschooling for middleschool). Well... my plans went awry.
First off... the school days had changed since my own school days. His school was 8.5 hours long (8-430), and we had a 30-40 minute commute. He didn't even get HOME until 5pm most days. Then it was meltdown/exhaustion time for him while I cooked. Then dinner/ bath/ bed. Start the next day all over. Morning madness. Then dinner/ bath/ bed. Morning Madness, dinner/ bath/ bed. Days where he had actives we lost entirely. He had no time to PLAY, much less learn. We also had to cut down his activities to ONE, period. More than one was simply too much, and even that one activity came with sacrifices. I only "had" him on weekends. And those started getting booked weeks and months in advance. Games on Sat mornings, bdays or playdates in the afternoon. Some Sundays we had, but most ended up with familial obligations, rotating playdates (since with 30 kids in the class there was a bday almost every saturday afternoon). There was just no TIME. And what little there was was filled with homework that caused meltdown after meltdown (my son was reading at a 4th grade level at age 3... but handwriting was torturous for him. Not dysgraphic, just physically painful coupled with adhd+boredom from busywork. Typing wasn't allowed, and the worksheets took him 1-2 hours to complete, and we had 10 to do each week).
Secondly... he lost his love for learning. He'd been in preschool and had been BURSTING at the seams to share what he was learning every day. The whole world was an adventure. By xmas break during K he'd wave and smile at his friends as he got off the bus, climb into the car still waving, wait till they were out of sight and just crumple. Bawling his eyes out. Absolutely miserable. He was BORED out of his mind. He loved his teacher (she was amazing), loved his classmates (raging extrovert, my son), and HATED school. He'd beg every day not to go back. He wouldn't even LOOK at any of his "works" (he went to montessori preschool, all the lessons/activites are called works) or books, much less pick something up for fun. He started faking being sick. He started MAKING himself sick. His "book" that had all of his school work steadily declined in quality. He started having to miss recess every day (because if you don't finish your work you don't get your "ticket to recess". He was an absolute mess.
((One of my great regrets was not pulling him out during xmas break.))
We had a choice of homeschooling, or paying 15k to get him into the local gifted program. Now, my son isn't HG, or PG, just normal old gifted that comes along with being ADHD. The school would have been amazing, and he loved the tour there (the kids had a 15 minute break every hour between classes and were encourage to run/ do cartwheels/ play with rocks going from class to class, were encouraged to ask as many off the wall Qs as they liked, could type their work or write it, go to the bathroom as often as they needed, did whatever level work they needed. Amaaaazing. School. We just didn't have the money for it. Theoretically possible to acquire, but difficult to say the least. So we figured we'd try homeschooling for a year and see how it went.
The first 6 months were pretty awful. Kiddo had meltdowns at anything that even LOOKED like it MIGHT involve learning. (Talk about heartbreaking, he didn't even want to learn new games). It took 6 solid months to undo most of the damage. 6 months before he'd ask questions, or answer in more than one word. My bright, curious little guy had just been crushed.
But by the end of the year, we were pretty good. So we kept at it. 4 years in, we're GREAT.
As a "why we started HS'ing" answer... ours is pretty common. Bad first year. Crushed kid. It caught me completely by surprise. And the biggest mistake I made was keeping him in school. But I don't think it was a mistake to send him in the first place.
The thing is... my son was in preschool 5 hours a day, 4 days a week. We had TONS of time for learning and play and family with that schedule. So as far as being in school half the time... that was a PHENOM choice for us. 8.5 hours a day of learning 20 letters, 10 numbers, 5 colors (the end of year goals), that he already knew? Dreadful choice.
Does my son miss the classroom / recess setting of preschool & awayschool? Often. He LOVES being surrounded by people. So I have to/ choose to set up his daily schedule so that is DOES include a lot of other people time. We're really lucky, in our area, that's pretty easy. There are over 20,000 registered homeschoolers in the Greater Seattle (SEA+Eastside+Northside) area... so there are tons of daytime classes, camps, and activities. Does he ask to go back to awayschool? Sometimes, absolutely. (He also asks to have cake for breakfast, drive the car, and make explosives. Most of the time, I say no.
How I TRY to set up his schedule is for him to have 2-4 hours a day of outside classes/ activities. That way he gets his people fix/ time to learn to interact & take instruction from people other than myself and out from under my eye. IF THERE WAS a school option that was only 4 hours a day long, I'd gladly send him. ((God, I'd really love for a language immersion 4 hour school as long as I'm wishing)). There isn't. So I piecemeal it.
Your fears are valid. Will they happen? Maybe, maybe not. But whether or not she's in awayschool or purely homeschooled... there's no reason NOT to keep up what you've already been doing as long as you've both got the TIME to.
Just my .02