1) It's not the topic, it's what you do with the topic. Virtually any topic can make for a good or bad essay.
2) Focus on whatever is
personal, detailed, honest and
revealing.
3) Try various ideas and see what approach is the most personal, detailed, honest and revealing.
4) There is some good advice here:
U.Va. Office of Admission Essays
5) re immature: that depends on what you say and how you say it. I don't think that this topic will
necessarily make you seem immature.