Hi Welcome to TE!!!
Just one issue with the bike, if you really have short legs and a long torso, the WSD bike may not be designed for you. WSD normally addresses a woman's build of long legs shorter upper torso so the bike may have a very short top tube, not a problem if you plan on riding fairly straight up and not bent over. The Pilot also has a fairly laid backed design which means you will ride sitting up more than most (which may explain why your butt hurt right away).
There are lots of discussions on this Board about proper bike fit. A bike is not a good deal, no matter how cheap, if it doesn't fit. Hopefully you took it out for a spin. If it doesn't feel comfortable keep looking around take your time. The shopping part is fun. Not certain your price range but you meant want to look at something like the Lemond Sarthe. Lemond's have longer top tubes than most bikes.
Anyway make sure the shop fits you properly and isn't just trying to dump a bike on you.
That being said, welcome to our little group - there's alot of great knowledgeable gals out there!!!