twins or strangers?

Andrea and I are only 11 months apart in age, so for one month out of the year we are twins, and I think that makes people assume that we'll actually look like twins. Of course, when I warn people that I look nothing like her (or anyone in my family, for that matter), they tend to think I'm just exaggerating. But when Andrea came to visit, everyone got to see first hand. 

When people finally see us together, I always get one of two reactions: "you guys are sisters?!?!" or "well, you have the same chin." Seriously, we've been told the chin thing on more than one occasion. I didn't even know chins had very distinguishable characteristics. 

So here are some of our best shots from Andrea's visit. What do you think? Total strangers or clearly twins? Or maybe we just have the same chin...