greek scene

Male Sophmore Transfer here, wondering the same thing

It's a pretty interesting setup, if I do say so myself! The short answer is that Greek life can be as large or as small of a part of your life on the Hilltop as you want. You can let your life revolve around your sisters or brothers, or if you aren't involved, you can almost pretend that sororities and fraternities don't exist at Georgetown at all.
I actually came to Georgetown in part because they did not have any officially-recognized Greek life (besides APO, coed community-service), but ended up joining DPE Professional Foreign Service Sorority in the spring of my freshman year mostly for the professional aspects of the organization. I have close friends in almost every single one of the other social and professional Greek organizations as well and there really isn't much competition among/between them like there can be at other universities that take Greek life more seriously.
The social-scene at Georgetown is predominantly club-oriented and these sororities and fraternities for most members are just another club that they are part of. While there are people who take their Greek involvement very, very seriously and dedicate a lot of time to it, the VAST MAJORITY of brothers and sisters are actively involved in a lot of other areas of campus as well, and their fraternity/sorority is just another piece of their Georgetown narrative.
As a transfer (or continuing sophomore) all of them should be available to you. Definitely talk to them at the clubs fair in September!