There could be other reasons to her mood...maybe a mood swing,
or that time of the month? Since you've already explained that it's
a small misunderstanding, cheer up! I'm sure she isn't that petty.
As long as you've tried to apologise to her, you're not in the
wrong! Just continue to be friendly to her, even if she gives you a
black face all the time. Better to make a friend than an enemy at
your workplace...especially when you're a new bird there. 
I think even if your working environment is full of ladies, it's
best to try and mix around with them. The point is not about
gossiping, it's about building friendship with them. And besides,
you won't feel so bad about your job if you have more friends
around you! Like I said, better to have more friends than
enemies!
