Reached my goal already and my brain decides to rain on my parade

For this month’s 30 day goal, I set a goal of signing 3 new clients for my private coaching package. I had taken a break from private coaching for the past year and had been having some doubt and lack of confidence that people would buy from me. I followed all the steps for making my goal, setting up a plan, following through – and I signed my 3rd client yesterday (only 11 days into the challenge!). However instead of having thoughts that lead to pride, joy, excitement, my brain is telling me I only sold out so fast bc I undercharged ($600 for 6 weeks of coaching). I do know that I have a tendency to underearn, and yet I also want my brain to think things that make me proud of my accomplishment. (Thoughts like “Holy smokes I did it!” etc.) Any support around shifting my thinking with this would be appreciated.