Being an Apologist _ You do not use your personal statement to explain why you lack certain skills or experience. The point of writing this short paragraph is to sell yourself and this involves highlighting your strengths instead of apologizing for your weaknesses which in itself is a sign of weakness. The time and place for discussing flaws in your suitability is the interview and at that point, you must focus on how you plan to overcome any holes in experience/skills etc.
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.