A PS is one of the most important components of your application because this document, when written correctly, will offer your readers, namely the admissions committee members, a quick glance into your life story so far and which direction you plan to take. You are inviting the reader to share your experiences as you disclose who you are as an applicant. Through your PS, you are providing them a general picture of your background and qualifications, knowledge of which will allow them to evaluate your suitability for admission to their school accurately.
In some ways you are very lucky because your experience of high school, hobbies and life experience will already be different from many UK/ home students so you should take advantage of this in your personal statement. But you also need to make 2 things very clear. Firstly, why do you want to study in the UK and secondly, you need to show that your English is of a good standard (usually IELTS 6ǌ or above). It is no good having IELTS 6Ǒ if you personal statement is full of grammar and spelling mistakes. But DO NOT pay for someone to write your personal statement for you on one of the many websites offering this service. If you have IELTS 6Ǒ, you do not have perfect native speaker style English and universities may reject your application if they suspect it is not your writing.