IMO, if you can't return this bike, you should grab a cheap fixed gear rear wheel, cog, and lockring, get someone qualified to install it for you, and ride this bike as a fixed gear beater. That way you can see if you like riding fixed gear and build up your riding skills. I would also take the opportunity to learn some bike mechanical skills.

As it is, if you sell it on Craigslist, it's going to be largely a write-off, since it's now used and has had some parts changed around.

Then, when you've reached a point where this bike no longer serves your needs and you have some money saved up, you can get a new, better ride and have less chance of messing it up with some kind of newb mistake.

I wouldn't worry too much about it being a women's style frame. I see men on step-through frames pretty often. Your average city commuter or DUI rider (90% of bike traffic, in other words) won't have a clue and won't be judging your frame, and as for the bike elitists, they'll always have something to judge you about. Just own it and have fun.