NaNoWriMo 2016
Remember, you don't need to be online to write! As Iammara said, it's not about quality so much as quantity. Just sit down and right. It doesn't matter where the story goes... we had a writing exercise in college where you took a roll of paper and stuck it in the typewriter (yeah, I'm that old!) and then you just type... what was called stream of consciousness. It doesn't matter where it goes... talk about your dog, your house, a teacher you had a crush on, your favorite sport/team, when you went to the zoo, summer camp, best pizza you ever had, etc.
It's a lot easier with a computer, and if you have a laptop/tablet, you can do it anywhere.
I'm rather shy, too, but once you make contact with someone from the local NaNoWriMo support group on the internet, they aren't strangers any more.
When you hook up with a buddy, you can actually have several buddies. You can find one that's doing the same type of novel you are doing--scifi, mystery, cozy, fantasy, hard-boiled detective, etc.
The bottom line is: if you want to do it, YOU CAN DO IT!