You said you only started thinking about this a few years ago. Is this because they were too young to seriously think about it or because the topic didn't occur to you?
I was surprised by a lot of things I thought I knew (but didn't) about being a father, being a Trad Catholic father, having a large family, homeschooling, etc.
For starters, I envisioned homeschooling as much more "do it yourself" whereas we ended up doing the typical drop-kids-off-for-music-classes almost every day of the week. When I was a kid we had 0 extracurricular activities, and we all liked it that way. Also the huge number of online classes and other scheduled classes (for example, online college classes). I thought it would be more "self teaching" or something at that age. My mom homeschooled a bit (she started when I was 16) so I really don't have much experience with it. The whole thing was an adventure for me. But I've learned a lot through raw experience, I'll tell you that much!
But my oldest, a boy, I thought I would have more time once he was "old enough" -- say at age 16. But to my shock, he was basically "gone" at 16. He was either doing SERIOUS school classes, gone to college classes, or working a job (full time when school was out). And then right after high school he actually went to college. I feel like I got gypped out of 2 years of "finishing" time I thought I would have.
Again, I had no clue about this before I had a 16 year old -- because my parents (Boomers) didn't have that issue. They did the typical 80's parenting thing -- basically the super-independent, throw them in public school, throw them in the deep end tactic. Which has its advantages, sure -- but also plenty of disadvantages. I suppose I learned a few things from how they (we) reacted to various news stories, what they shouted at the TV set, etc. Which was good, I suppose. And we had a lot of conversations (again, why not? we were practically adults at 13 or 15). Plus, I wasn't from a "college family" so I wasn't on a college track. I spent a lot of time at home writing computer programs and games as a teenager. Just a completely different experience compared with the family I'm heading up now.