Aeda, GC can be addictive, and I find it is especially so around Rush time (for PNMs and Alums alike!) but there's no sense in stressing out about it now. Definitely do your research though, look on the national and chapter websites, find out if the chapters on your campus are really involved in their philanthropy and/or other campus activities. Really evaluate what you want in a sorority and what you think you can give to a group - knowing those two things will be a big help in recruitment because guaranteed you'll be asked something along those lines...
As far as having two favorites going in, that's understandable having deferred rush - that's part of the argument against it also though. It's ok to have your opinions going in, it's only natural, but don't discount the other groups either. Like I said, do your research and try to give every group a fair shake during parties - I promise you won't regret it
And I'm sure I'm speaking for many of us here when I say we're looking forward to hearing your recruitment story in February, so definitely keep us posted!