I have joint custody, but she is the primary. Do anyone know...Do I have a legal right to say "no" to home-schooling?
That depends on your local laws and the separation agreement. Get that advice from an attorney, this is serious business.
Personally, I have no issue with home schooling as such. It worked well for our kids, but it took much hard work. We set high standards, used good curriculum, and had assistance from certified teachers through accredited "virtual academies". It wasn't a case of just throwing some workbooks at the kids and saying "Here, work on these".
The problem comes with parents who use home schooling to avoid a real education, to stay away from topics such as evolution, sex education, civics, etc. that conflict with their beliefs or that they consider "too hard" (literature, math and science). Another problem is parents who don't take the time and effort committment for home schooling seriously. We knew several families like that, including some of my ex-in-laws. I suspect my Ex would have done likewise, if I hadn't been around (I agreed to home schooling because I think the public schools in our town are too easy!).
Is your ex really capable of dedicating the time that home-schooling requires? If she is working and a single parent, I don't think it's possible. We could barely keep up with two parents involved, with my Ex being a stay-at-home and me having the evening shift.
Another concern is will she use the days with your daughter for things "more important" than education: going out in "service"? After all, why bother with worldly education when "so little time remains"?
So my advice is to get a professional opinion on how much say you have in the home-schooling decision, and no matter which way that turns out to be as much involved with your daughter's education as you possiibly can be. If your Ex is serious about home schooling, she should appreciate the help and support. If she isn't, your involvement will be unpleasant for her (and in that case she deserves it, so too bad for her!).
Good luck, and keep us informed on how it works out.
GLT