Does this make a friend's actions justifiable?

Ok well I never understood why one of my friends had such a thing against me 'til recently...the thing is that this friend seemed more of enemy than anything, she would be on the verge of laughing when I had a problem but angry when I achieved something so idk I never really liked her but I have been feeling soory for her 'cause she failed high school, she has to work with her parents by force, she has no freedom, & she can't even get a decent job... I mean was she just jealous?, it was obvious to me and my friends that she has always been materlistic so I mean could it be that? Because I feel like to her I represented an image of what she couldn't have... and that is probably why she would try ruining my art or new things, try tripping me, embarassing me, hitting me, making fun of me, telling me I was a slut?!?, or that I didn't deserve anything like being in Honor classes and such?