Should I ask this girl if/why she hates me?

In November, I asked out a girl that I had known for a few months (we weren’t best friends, but we were friendly with each other), and she politely declined, saying “I’m kind of seeing someone… But thank you for asking”.

A few days later she posted as her Facebook status: “I’m pretty optimistic for someone who was just shot down”. And to it, I commented “Story of my life”. She then replied “shit happens” and then deleted the whole thread. My intentions were good-humoured, but I think I made her mad.

I think this is the reason that we haven’t spoken since. We volunteer at the same organization, but whenever we’re in the same room, she never acknowledges me. Both of the times I invited her to Facebook events, she replied “no” almost instantly.

We were both just elected to the org’s board of executives, and we have a meeting tonight. Should I…
a) Confront her and ask her what’s up and apologize for my shittiness?
b) Ask one of the directors about what to do?
c) Do nothing?

I should probably mention that I’m 18 and she’s 21.