Okay.
"She really blew me away by saying that she wouldn't be coming back for classes in the next semester." Correctly used?
OR
"They blew the rival team away three to one in the semi-finals." OK?
Okay.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.