Your friend isn't a parent yet, she's never homeschooled, and she hasn't parented your child. I've found that people like to talk about the children they meet, and there are people who like to give advice - maybe because your friend also happens to be a dr she's prone to enjoying giving out advice
Although it wasn't the same advice, we've run into this situation with parents in things other than just gifted parenting - one for instance is having children come into your family through adoption. People who are not part of our immediate family have felt completely free to offer up all kinds of advice ranging from silly to clueless to downright horrid things to say in front of the very children they are giving us parenting advice on. Moving on from the gifted comments and the adoption comments, way back to when my ds was only a few months old, he had a very large head. You can't believe the comments complete strangers, and even the nurse at the hospital, had to say about his very large head!
The thing I eventually started doing was just not sharing much unless there was a reason to share, and when people I don't know well comment on things they are clueless about I just ignore, move on to a different topic of conversation. In the grand scheme of things, it doesn't matter much what anyone else thinks about your choices for your childrens' education, and it doesn't really matter if they realize what an amazingly smart child you have (unless they are administrators at a school you want to get your child into lol!) - what matters is that you make the best decisions you can based on what you know about your child. Feel confident in that, enjoy your friends for the reasons you became friends to begin with, and ignore the rest
Best wishes,
polarbear
