Start answering this assignment by deciding who and what you are - pop musician, professional athlete, movie star? What awards have you won? What outstanding performances have been highlights of your career to this point? Why were these incidents outstanding?
Once you have figured out what you have done that has made you famous, pick the event or experience that you want to have happen first and make up a date for when it happened. It might be easiest to have your three entries build on each other.
For example, if you decide to be a pop musician, your first entry could talk about the contract you signed that day to record a new composition. You could talk about why you feel the song will be a hit, what musicians will be involved in the recording, and what the video of the song might involve. Your second entry could be dated the day after the video is released, and you could record the rave reviews it is receiving from critics and fans alike. Your third entry could be after you have been given a major award in recognition of your musicianship and the high sales of the recent release.