Teeth!?!

Heaven

My daughters babysitter mentioned something about her possibly teething since she's been drooling & fussy. We snapped this picture but I'm not sure.

I've read that they can teeth at early as 2 months, but not get their teeth til 6 months. So I wasn't sure. Plus I know its common for them to get their bottom teeth first. But I'm a first time mom so please, give me opinions.