Undergraduate / "All I can do is be me- significant experiences that helped to define you as a person [4]

Apart from the grammar, I think you should use a different word than "unintelligent." When a college admissions person reads that, they'll think that you have low self-confidence, since "unintelligent" is a very derogatory word. I would change the sentence to say something along the lines of "I was never the most intelligent person in my school, etc.."

Never make yourself look bad in the essay. It's one thing to say you're not the best, but to say you are bad, that's a problem.