First off: our experiences won't work for your essay. This is supposed to be a personal story, not a plagiarized paper.
Second: don't spell like that in your essay, unless you ant it to be about the time "I didn't use SpellCheck yet again..."
Now on to your question...
What I would do: Think about who you are. What kind of person are you? Are you gruff or kind, dynamic or calm?
Then, think about all the big experiences you've had in life. Trips, getting a new pet or sibling, a death, everything counts!
Then, try to link together an event with a characteristic about who you are. For example, the death of your grandma might have made you more caring. Or your trip to Europe made you more open to others.
Then write your essay. Start with a strong lead, describing the event you are talking about. For example:
The city of xxx boasts over 18 different nationalities, speaking over 10 languages. So on and so forth, write your essay.
Then, write about how it (in this case, a trip to Europe) made you YOU.
For your conclusion, do something like this:
I have found myself ot be open, and non-judgemental. Blah blah blah.
*Tip: I know that the question says to pick some big event in your life, but try to think of a small event that became big only because it changed who you are. I interviewed a college admissions person who said that doing that is GREAT!
End it with