"All I can do is be me- significant experiences that helped to define you as a person

"All I can do is be me, whoever that is."

I actually never believed in myself. I see my self as a person who is unintelligent. One experience of mine that helped me to define me as a person was my parents. There was this time when my grades in school are not that high. I always envy my classmates who have grades 90 above. I could really see how proud their parents are when they go up in stage and put the medals on their children's neck. I've always wanted to come up on stage and make my parents proud. "You don't need that high of grade to make us proud." My parents once said to me. After that, I realized that school grades isn't the only thing that can make your parents proud. I can make them proud by: 1.) Always try my best in studying, doing my home works and showing them I'm not slacking off. 2.) Doing the right thing. Before I do something, always think about wether it's the right thing and it would make my parents proud of me. 3.) Be a good person and be responsible. Don't be so immature that my parents have to keep an eye on me. In that way my parents will surely be proud of me.

You can also write about your ability, interest and achievement.

I see my self as a person who is unintelligent.
I have often seen my self as a person who is unintelligent. One experience of mine that helped me to define myself as a person was my parents. There was this time when my grades in school are were not that high. I always envied my classmates who had grades 90 and above. --- do you see how I am putting all the verbs in the past tense? If you work on conjugating verbs, it will help you very much.

past tense:
I could really see how proud their parents were when they went...

I like the ending!!!!!---> In that way my parents will surely be proud of me.

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.