First Doctors Visit today

So today at 4:00 I have my first doctors visit where I will get checked out and schedule an ultra sound I am so excited I know its still early in my pregnancy but I cant wait to see our little guy/gal.
I was reading yesterday that the earliest you can find out what your having is between 6-18 weeks but most dont till like 6 months, and as far as I know im only 3 weeks.