It either means she likes you or has bipolar. I'm joking about the bipolar part, but she probably likes you. Don't take my word for it, she probably just blushes easily.
What does it mean when a girl blushes with you but is angry at you and does not want to talk to you?
She probably really likes you... Look up the term "Tsundere" that is what she is... That's what some girls usually do when they like a guy... I did it once...