That's a conversation that needs to be had: which aspect of asynchrony is the least/most detrimental at this time.
Beautifully put! And as Aquinas' school placement thread reminds me, a constantly moving target.
Listening to everyone's stories, I think a key consideration is where your daughter naturally tends to find her friends. Myself, I have always gravitated to people older than me (my mother claims when I was two I hung out with four-year olds). Skipping wasn't an option, but by the time I got to high school I was excruciatingly bored, doing well enough academically though doing nothing, and indescribably desperate to get out and start my life. I managed to find an unusual way at that time of compressing our then 5 years of high school into 3, graduating two years early. Which had me starting university with the kids two years older - who were the ones I spent all my time with anyway.
What would have been socially brutal for me would have been remaining behind in high school when the age group I could relate to moved on. I still shudder even to contemplate it. At university, I was finally able to come alive and be myself.
But I was extremely independent, no extra "Es", and always more comfortable with older peers. My own DS12 has academic needs considerably more extreme than my own ever were, but for him I can't even begin to fathom the possibility of moving to a new city on his own at 16, and independently taking on the challenges of university. Not a chance! Some kind of interim mixture of on-line and local university classes, mixed with chugging through non-math and science high school courses at the usual rate, may be a far more appropriate route for him. When I think of his future, I am looking to bluemagic and notherben as more likely models than my own pathway. To each his own asynchrony, indeed.
ETA: As a champion what-iffer, I totally sympathize with your currently whirling head. And looking at my own DS, totally agree with all the cautions above. A double grade skip could be disastrous for many kids. But if you are going to cover every contingency, do throw in: what if.... the second skip is the best thing that ever happened to her? She has her reasons to be that excited; listen closely to them. My parents were horrified. I was alive for the first time in my life.
