in a ways yeah and no .just because u don't believe in the supernatual doesn't mean ur close minded to everything else.. but where u can gauge if u are or not.... if some kind of supernatural experience would happen would u stay blind to it or acknowledge that it could be the supernatural ..u don't have to believe in it but be open to the possibility of it .
Open minded is an often misused term by people who believe in things without any evidence- they like to decry anyone who actually requires evidence as "closed minded" when in fact it just makes the skeptic rational.
"Open minded" means a person is willing to change a previously held belief if provided compelling evidence to the contrary- not that they accept any outrageous claim as possible. It's actually likely your friend is the definition of closed minded- a person who would not change his beliefs no matter what evidence is shown to the contrary. People who believe in the supernatural are notorious for clinging to those beliefs even when they are debunked.
No you are not close minded for that. Instead, you are rather more open minded than your friend is. How are you more open minded? Your friend considers only one solution: the supernatural. You consider that there are plenty of other solutions to the question or the problem.
Just as OrangeBlossom said: I have an open mind, but its not so open that my brains fall out. However, if something that you could not explain except by "supernatural" were to happen in your life and you still chose to deny that it was beyond your explanation, then I would consider that closed-mindedness.
People who believe in the supernatural tend to be the ones who are closed minded. They don't have any desire to think or investigate, they have no need to, it's easier to just say, it was magic, end of debate.