More than anything, you should want to change your life because you care about and value yourself.
Building a positive self-image may take time, but putting in consistent daily effort is a good place to start. Every day, make sure you remind yourself that you are working toward changing your life for the better. Far too often, many people choose not to change at all. By working on bettering yourself and putting in the effort to change, you are already taking better care of yourself than you may ever have before. Put yourself first!