I had my period on October 20, 2011 and haven't had one since. How far am I

Maybe... but see a doctor and take a test both.. there are other things that can cause a period to stop other than pregnancy. Most you do NOT want to ignore.

No all that means is that you have not had a period. It can be from an infection, a STD, or merely a hormone imbalance.

So you find out if you are pregnant by having a pregancy test.