Your question should be either " Why is there school?" or "Why are there schools?" Considering you need to work on using proper grammar, I would say that is one reason you should go. As an employer, I do not hire people who cannot fill out an application correctly , using proper grammar.
Without education you would be lost, school is there so that children will go to school, learn as much as they can, and apply that knowledge to useful and necessary services in society. Think of America as a computer, a computer runs most efficiently when all parts are in place, in good condition, and up to date with the latest technology. However when one part stops performing correctly it can in turn have a negative impact on the computer as a whole. If no-one went to school it would be very hard for past generations to pass down knowledge of history and promote new discoveries in technology as a society, over time useful and necessary information would be lost in time and this would result in future generations regressing rather than progressing. So you see school is very important because without it all the modern items such as phones computers and games that you hold precious would not be in place, and modern services like reliable hospitals and grocery stores would not be in place. Go to school and take pride in how much knowledge you can obtain. Ambition without knowledge and action is fantasy.