Creativity: Reflective Writing

I've never really been comfortable talking about myself. I quite enjoy writing essays about defined, impersonal or academic topics because there are definite answers. However, this assignment has asked us to write an essay which is very much so indefinite in it's outcome and conclusion. I have been asked to write about myself, to write of a certain experience that has affected me emotionally or taught me a lesson. It could be a negative or positive experience. I am finding it a little difficult to fathom the concept of self reflection. I take criticism fairly well when it comes to impersonal projects as there are right and wrong answers - there are simple ways of correcting your work, but I'm not sure how comfortable I am with writing about my feelings or experiences and then being critiqued them. 

In fact, the input of "I feel" and "I think" within an essay will feel a little peculiar, that's for sure, but, all that aside, I feel this assignment will be highly beneficial on some personal level once I overcome how uncomfortable it may be.