LDMom,
I'm definitely afraid that if I homeschool him, it will become impossible for us to fit into the education system again. He is age-grade on reading (self-taught) and probably would be on every subject if I was actively homeschooling him.
I wasn't sure what "he's age-grade on reading" means. Could you explain please?
While I am sure it is true that homeschooling will allow for more advancement, realistically if he's very PG and already give grades ahead I don't think you will stop, or necessarily even slow, his fast rate of advancement by putting him in school. It can be easy to feel like you sort of have control over it by the decisions you make but for some driven HG and PG kids it will just keep going no matter what you do.
One question you may want to consider is if you have it as an option to homeschool over the long term. For a kid who needs five years grade skip I think you have two choices:
1. Homeschool (and accept all that goes with that in terms of responsibility and possible loss of wages).
2. Accept that they likely are not going to be fully challenged in school academically and that you may have to make some compromises socially. This may sound negative but it certainly works out for many kids and I don't believe there is a reason at the outset to assume that it won't.
While early college has been a positive decision for our family, I personally would be wary of a five year grade skip for a student attending school. I wouldn't want my seven year old with twelve year olds or my twelve year old with seventeen year olds. Often the halls of middle and high schools aren't the nicest of all places. I personally feel much more comfortable with early college because the people attending are adults and especially with a very young student it is clear you aren't expecting that to also be the place where they make the bulk of their friends.
Overall though I agree with the sentiment that it is only guess work. Make the best decision you can for next year and take it one year at a time.