I got all defensive for no reason.?

I have a white friend, who didn't know I was a Muslim. Just moved school. Anyway, when I told her I was a Muslim. I got defensive, I have no idea why. I think it's because she'll reject me for my faith. The thing is she was fine with it, she was shocked because I look latino. However; how do you think I should tell a friend I am a Muslim next time?