sorority rush

No you have just the same chance of getting a bid.
Now getting a bid to a specific type of sorority, might be less likely. If you just want a bid SOMEWHERE and are really looking to join a sorority for things like friendship and not things like a faux "tier" title, then you have a good shot.
Just be open to where ever you get a bid to. I guarantee ANY girl, sophomore, freshman or whatever, would get a bid from any sorority at UD, just not the ONE they get their mind set on.

You're not less likely to get a bid if it's your first time rushing (tons of girls do this) but if you rushed freshman year and dropped out when the ABSOLUTE ONLY HOUSE FOR U 4EAEAE dropped you....some houses might take that the wrong way.

If it's your first time rushing, you were involved in other things your freshman year and if you don't have a low GPA it will not be held against you that you're a sophomore. If you weren't involved, have low grades, or rushed and dropped that may hurt your chances but nothing can definitively say you won't get a bid! I rushed as a sophomore, and so did a lot of my friends. I know at least one person in every single chapter that got a bid as a sophomore so i really don't think it makes that big of a difference.