People talk about bullying, but you can be your own bully in some ways. You can be the person who is standing in the way of your success, and that was the case for me.

This quote means that it isn’t only other people who can be bullies–sometimes, the person who is preventing their own success is themselves. In this quote, the speaker is referring to their own past experience, in which they were the one who was getting in the way of their own success. They were their own bully.