Anyone here a fraternal twin?

STW14

For the past 6 years everytime I would go to my doctor for my annual she would remind me that my chances of having twins are 1 in 17.  Now that we are expecting I can't help but hear my doctor say "1 in 17, 1 in17, 1 in 17"...  I'm a little nervous.

We go for our first appointment November 2nd and by then I will be almost 8 weeks.  DH was really hoping for an ultrasound then, but since we haven't had any problems I told him that we wouldn't until 11-13 weeks when/if we decide to do the genetic testing.  He's freaking out that we won't know if there's two until then. 

Anyone here a fraternal twin or twins run in your maternal line?  Are you worried about having twins?