2nd Pregnancy?

My 11 month old daughter was born Jan 2007 and now I'm pregnant again with my second child. I believe I'm about 6 months pregnant. I had my last period either last week of June or first week of July. So what I want to know is does the pregnancy after the firstborn last only 8 months instead of the 9 that you had with firstborn? I heard that after your first born the babies come after 8 months. If that is so then my due date would either be the end of February or early March. That's not too far away. Exciting. Oh another thing is, is it possible at this point to find out the of my child?