Why am I being labelled as weird for being a private person?

[Longwaytogo]

I'm 25, very extroverted and love socializing with people. I work as a social media manager so I spend all day on social networks. I find them entertaining and fun but I never share my personal life on them. I like connecting with interesting people to discuss current issues and share fun articles to read. All my friends post their vacation photos, status updates, engagement announcements, wedding and pregnancy photos and urge me to do the same, which I hate. If they're ok with it, good for them, but that's not for me. I recently got engaged to the love of my life a week ago and I've only told my close friends. I don't plan to announce it on Facebook and my fiancé and I dread the idea of a big wedding so we plan to elope. My friends keep urging me to announce it on Facebook ( like wtf?)
My friend told me being so secretive makes me a sociopath because deep down everyone wants to be the center of attention. I really don't. I just want to live my life, mind my business and keep my private life private. Does that make my a sociopath?