I’m applying to brown and I wanted someone to look over my essay and let me know what they think. Should I add or remove anything? Also any grammar or spelling advice would be a great help.
“Is this all that I’ll learn in college?” I said to myself as I pushed aside my completed Calculus homework and began to work on my programming assignment. I majored in computer science with the goal of becoming an entrepreneur, but I feel that I lack the needed skills to become one. I have learned a great deal of math and programming over the past two years but nothing about business or skills needed to start a successful start-up someday. I looked at the possibility of taking some of these courses once I transfer, but the chances of doing so is unlikely. Most schools have very strict curriculums with very little room for classes outside your major. Even elective classes had restrictions because they specified what type of elective; history, humanities or art. You have no choice but to follow the course that the school has set. If I desired to take a class not related to your major you either overload your semesters to make them fit or hope that the class will qualify another requirement for you major. This is with the exception of Brown University. Brown’s open curriculum grants me the freedom to take classes that will teach me the skills needed to achieve my goal of becoming an entrepreneur.
For future reference, you should take a thread like this to the College Essays board where reliable people can read your essays and offer to do this type of consultation in a private message. This reduces the risk of plagiarism and the release of personal information. Don’t worry about my creds though; all my applications are done and I’m just sitting back waiting for decisions.
“start a successful start-up someday.”
Use a different active verb like “Run” or “Manage”.
" Even elective classes had restrictions because they specified what type of elective; history, humanities or art."
Instead of a semicolon, use a colon ( : )
“If I desired to take a class not related to your major you either overload your semesters to make them fit or hope that the class will qualify another requirement for you major.”
You switch the persons here. Since you used ‘you’ in the previous sentence, stick to ‘you’ in this one, unless you wish to switch all the ‘you’ to ‘I’. That’s fine too.
“This is with the exception of Brown University.”
Switch from passive voice to active voice and say “The exception is Brown University.”
Hope this helped. 
I have made some modifications:
“Is this all that I’ll learn in college?” I thought about that as I pushed aside my completed Calculus homework, and charged at my programming assignment.
I majored in computer science with the goal of becoming an entrepreneur, but I felt that I lacked the needed skills to become one. I learned a great deal of math and programming over the past two years, but I had nothing about business or skills needed to run a successful start-up. I looked at the possibilities of taking some of these courses once I transferred, but the chances of doing that were unlikely.
Most universities had very strict curricula with few opportunities for classes outside of one’s major. Even elective courses had restrictions where they specified what type of electives in history, humanities or art one had to choose. So, I had no choice, but to follow the courses that the school had set. If I desired to take a class unrelated to my major, one either overloaded in several semesters, or hoped that the classes would qualified in another requirement of one’s major.
This was true except for Brown University. Brown’s open curricula granted me the freedom to take classes that would help me to develop the skills needed to achieve my goal of becoming an entrepreneur.
At this point, you should scrap the entire essay because you posted it publicly on a forum on the Internet where posts cannot be deleted by the user.
I also think that you should spend more of your “Why Brown” essay talking about… Brown. Instead of saying, “Most colleges don’t do X,Y,and Z. But Brown does. The end,” you can scrap the third paragraph and write more about what courses outside of your major / departments of study you would be interested in and why you feel that these courses, or Brown’s approach to education in general, will make you a better entrepreneur.