Is it possible for a girl to only like one girl but be straight............?

because this one girl used to always look at me in the 8th grade in middle school she would stare at me so much. i could tell she wanted me so bad. we both were 14 years old then. but now we are both 18 and we dont even go to the same school now but i happen to run across her face book profile and i saw beside interest in boys and that she was straight and i then i started thinking is it possible for a girl to only like one girl but be straight. Or did she just go though a faze or something.