Thoughts flit into your mind all the time. They are just thoughts. They are not absolute truths. Those thoughts don’t describe you. Just because you are thinking or feeling unworthy, does not mean that you are not worthy.
When you have intrusive, negative or scary thoughts you don’t have to take them as truths. Rather notice your thoughts as an observer, “I notice that I am thinking about how scary this next step is and that I am not worthy of their trust in me.”
This drives a wedge between yourself and the thought. And from there, you can flick away those thoughts and change your thoughts to more productive ones. “This is a big step for me. It’s a great opportunity. If they asked me to do this, then they believe in me. I got this.”