What Does This ALT Level Of 67 Indicate?

Hi, I am an 18 year old female. In the past year I have taken 4 blood tests which have shown my ALT levels to be 91, 70, 53, and 67 in that respective order. 67 is the most current ALT level. What exactly does this mean? Do I have a fatty liver? What should I do to lower my ALT level to normal?