Some students get so wrapped up in writing about their chosen experience that they end up forgetting about themselves. Talking about yourself may feel uncomfortable, but that is the point of the college essay—to show the committee who you are and why you will thrive at their school.
Colleges, particularly Ivy League schools, want students who are unique and stand out in character, values, academics, commitment, and responsibilities. All of this necessitates that you talk about you.
Regardless of what you write about, make sure that it is a springboard to talking about you as a student, as a human, and as someone who has distinctive qualities.