Does this make me a bad person?

I think i made a major mistake. i took my best friends little brother out for a movie. i am a 16 year old girl and he is 14. We bumped into eachother at a mall and i invited him to come with me, a movie a lone is boring. Anyways, i even bought him popcorn and a drink and even a small dinner after.

He texts me today asking if " we are boyfriend and girlfriend". i already have one. He just did something to make me mad, he changed his facebook profile to in a relationship, even though i have yet to respond to him. I just feel now this is my fault. If my friend will eventually find out, who do i tell first? I would let my bf, but he may be mean. sometimes i feel i am too nice but i still do not see a problem with that in the end.