When someone says "you jinxed me" It means you said something and made it so it might happen... Example; You: I can't believe we got locked out of the house. Friend: Atleast its not raining *it begins to rain* You: Ugh, you jinxed it!

Like Luxyca said , you jinxed it means that you made something that people don't want them to happen happen. Most of the time, they are bad stuff. I think he was kidding. Like AT LEAST IT'S NOT RAINING, then IT started to rain, then if he said you jinxed it . IT means that now it is .