If you have a strong desire to go to college or university you shouldn't let anything stand in your way. Maybe you think that you're not a very good writer, and you think that this is holding you back from getting a higher education. Henry Ford said that if you think you can, or if you think you can't, you're right. Your belief that your writing is poor may be holding you back from even trying, or may be becoming a self-fulfilling prophecy by you behaving as if you are a bad writer.
First, you should take an objective look at your writing. Maybe it's not that you're a bad writer, but that you don't enjoy writing. Have someone you know look at your writing, and ask for their honest feedback. An even better way to assess your writing is to have an unbiased third-party look at your writing. Make sure that they have a background in writing, and you might even consider hiring an essay editing company to look over your work and tell you honestly how it ranks. These people won't worry about your feelings, and will be able to deliver the news without a sugar coating.
Once you get your feedback from others, take an inventory as to where you stand in regards to your writing. If it's true that you're not a very good writer at this state, that's OK. But you may be shocked to find that you're a good writer, but perhaps someone told you a long time ago that you're not. The thing with writing is that it's a skill. While it's true that some people are born with more natural ability, and writing comes easily for them, it doesn't mean that you can't learn to write better. Take this setback as an opportunity to learn a valuable skill. Writing is something that, unlike a subject like Algebra, you'll use every day. It can help you in many aspects of your life, and is worth the time invested in learning how to do it better.
The problem that occurs is that you need the essay written now, because scholarship deadlines are approaching and although you've resolved to become a better writer, you need to be able to fill out the applications and win the awards in order to go to college and learn to write better. In this case outsourcing is your friend. There are many places that will help you edit your essay so that it sounds good. Once you get the initial first draft of your essay finished, you can submit the draft and an essay editing company will make corrections to it. There are many companies that offer unlimited edits. Test out that feature and keep resubmitting it until it's perfect. Best of luck to you in your scholarship hunt!
Besides scholarships there are many graduate school grants [http://gradschoolgrants.org/] that you can get now that you've figured out how to write better. There's also a bunch of graduate school fellowships [http://gradschoolgrants.org/graduate-school-fellowships.html] that may interest you.