Congratulations on putting together the first draft of your personal statement!
Don't worry if it sounds disjointed, you have missed bits out or it's too long or too short - you can correct these things later on.
First of all, read through what you've written slowly and try to read it from someone else's point of view.
Make sure it's easy to read and not confusing. Have you said everything you want to say without under or over-selling yourself?
If you are confused by reading your own personal statement, it is likely anyone else reading it will be too (including the admissions tutors!).
Next - get other people to read it. Ask your family, friends, teachers and anyone else who you think will be able to give you a good opinion.
As well as checking for spelling and grammar mistakes, they will be able to tell you if they think there are some things you may have missed out.
Also show it to your head of year at school or career adviser, as people like this will have seen a lot of personal statements and therefore know what a good personal statement looks like.
You could also get people on the Internet to look at your statement, and see what they think.
There are many web based communities where you can post your personal statement or email it to people, and they will happily give you advice for free.
4000 characters is the maximum amount of text you can squash into the space available on the form, but it is also a way of disciplining your writing in your UCAS personal statement so that you have to order and structure what you say and select only the most important information from your various experiences and lists of qualities which the admissions tutor needs to know. UCAS suggest that the best way to ensure you enter your personal statement correctly is to prepare your personal statement offline using a word-processing package and copy and paste it into the space allocated.