I found more context online, which is necessary for understanding this sentence:
REBECCA See that guy?
ENID Which one?
REBECCA He gives me a total boner!
ENID He's like the biggest idiot of all time!
The guy, a COLLEGE SOPHOMORE, walks by them with two friends.
COLLEGE SOPHOMORE Are you guys up for some reggae tonight?
REBECCA Okay, you're right.
Rebecca is responding to Enid's statement that the guy is "the biggest idiot of all time." She's not answering his question about reggae, she is agreeing with Enid that he's an idiot.