What would you do?

So there's this woman that works with my husband. I've seen her at various events/parties, but I don't really know her. She saw me at a party this summer (we were both drunk) and she said, "hey, there's something I want to ask you... you've always been really nice to me and you're beautiful and I don't have many girlfriends but I was wondering if you'd be my bridesmaid?!" And I'm laying on this couch, drunk, looking at her like, is she serious?? And I smiled and said "surrrre" and she said, "I'm totally going to ask you again when we're sober so you know I'm for real!" Well, a couple months later, she sees me at another party. She comes over while I'm doing a shot and she says, "hey, so I wanted to get your phone number so that we can start going for dress shopping.."

So my dilemma...

-I really don't know this girl.

-I would rather not be in a wedding unless I'm close to the person.

-I feel bad telling her no now when I said sure 2 months ago.

-God willing, I'll be pregnant by the time of her wedding.

-And my husband said, "oh man, you've got to get out of this."

So what would you do? I want your thoughts.

If you'd decline now and apologize, what would you say to her?

Is it completely awful of me to tell her no now?

FYI - Looks like she's got the wedding planned for August.