Think about this creatively. Page 190 is about 2/3 through the book. If you wrote it at your age, that would be about age 12. Or you could be creative and write it at an older age and have it be a part in the future.
This is where the college learns something about you, either a significant event in the past, or who you aim to be or your goals. This part is up to you, but it has to be about you. My guess is that they want you to start on page 190, but you could also write a traditional essay about the events on page 190.