Dating A Brother of A Friend?

I did not mean to invite Justin. I seriously thought I was asking him if he would be catching The Simpsons. Which of course, I should have asked - Are you going to watch The Simpsons? Oh wait! I did ask this. But Justin responded and one thing led to another, and he could not go, but he was polite enough to thank me for the invitation?

Wait! Invitation? I did? So, by now, his sister should have known that I invited him. His sister's best friend would know too. And now, I would be a laughing stock, because although I knew his sister for a longer time period, I did not ask her, but I asked her cute brother. Oh brother!