Help Fellow Entrepreneurs

Hi Group, I'm getting ready to propose some new contracts with some agencies and I am asking for a lot of $$$. Way more than I feel comfortable asking for because I tend to lowball myself! I took a pricey money mindset course and I don't feel it helped at all. How can I prepare myself for these meetings and not peddle back on my prices?

Also I just found out one of my competitors is charging almost three times more than what I'm actually considering proposing. So, even though I am asking for way lower than what she is, I still feel super duper uncomfortable. Help!