This is supposed to be something that happened in your life and since I don't know you I can't really help you. Something important celebration could be a Sweet 16 for example. Its something that happened to you that made you really happy. Maybe you have become an aunt or you got your drivers license. Pick something from your life that made you feel like celebrating and put it on paper. :)
I cant really help you much with this since the answer has to be something from your own experience, think of an event that has impacted you or something that you remember like it happened yesterday, describe how you felt at that moment that the event happened, describe what happened
