too late to rush as a junior?

I'm currently a sophomore, but I didn't rush freshman year because I wanted to check out other commitments. Didn't rush sophomore year due to family/schedule conflicts. I want to go through with spring rush, which is informal, but many of my friends involved in Greek life advised me to wait for the fall instead. My only worry, however, is that it will be too late to rush in the fall. They told me that there is actually a large quota for juniors but can anyone else confirm this? I trust my friends, but it would be comforting to receive more information. Thanks!