The other thing that helped me in general with anyone who disapproved of homeschooling was my realizing that it doesn't matter what "they" think. (Whoever "they" are.) Letting go of the need to persuade people is the best thing you can do. If they judge you badly, so what? It's not open for debate. You're the mom. The decision is made. They are free to have their opinions, but it doesn't have to affect you one iota.
And if you stop feeling defensive, a funny thing happens: they stop sensing that they've found a weak point and the assaults stop.
Exactly. The beginning is hard. People are finding out you are homeschooling and you have the need to explain yourself. BTDT I remember getting into a fight with our very good friends when they found out about our plans. Never mind that it was them who had suggested only a few months earlier that homeschooling could be the right choice for us.
Once you are confident enough about homeschool and your own choice, once you no longer care what others think, things get much better.
You do not own anybody an explanation. You can tell them why you did it, but then move on. Most of the people argue because of their own insecurity. If you homeschool perhaps they should/should have hs too. You will meet people who are supportive and people who don't get it. It's ok.
As for your own family, they may need time to get used to the idea. They may become more supportive once they see what's your child learning. That happened with MIL and FIL. The only thing I would make sure about is that all their concerns are discussed out of your son's earshot.
Good luck
