I am very open about my BDSM lifestyle. My Dom and I are in a committed relationship. My mother knows and she has never said anything negative about it. But she's kinky in her own way so... lol
I have lost one friend of 11 years over it, but not because he didn't approve of what I was doing. He was upset that I would not allow him to be my Dom. He wanted me to experiment and explore my submissive side, but was truly hurt when I allowed my Master to collar me. It affected him way worse than I thought it would.
In my opinion... be yourself. Do what makes you happy. And don't let anyone or anything hold you back. If you choose to keep your lifestyle a mystery, than so be it. But if you are open about it, your true friends will support you regardless and your family will love you just the same.
I love being open about it. Even today, with bruises from last nights play session, my mother just chuckled a little and gave me a hug. I don't have to bs my way through explanations. People just know. And since He has made me happier than I've ever been, it is accepted as normal.