You have a very good point. I do the same thing. I think I have shared about Bitcoin only with four of my friends, and one of them is already an expert, while the other two are still learning. One of them just bought some Bitcoin and later sold it. The other one is still holding a small portion. I have a big friend circle, yet I do not discuss Bitcoin with them. The reason is different, Bitcoin is banned in my country, and it is illegal to use it. So, I can't share it with everyone. Also, I do not want to tell people that I own Bitcoin. They could easily report to the police if they want me to suffer.