Feeling a sort of Guilt.. Need your thoughts pls.

Few months I got an offer from one of the WITCH, and the most surprising factor was, they were ready to wait 90 days when no others companies did. It was only because of this offer I put down papers. Towards the end of the third month, I got another offer from company B. Though the package and all is same, the team I interviewed for and project that I am going to be part of excited me and I am willing to join Company B.

Now when I go and say her, I am not joining CTS, I don't know how she's gonna respond/react.Like literally 3 months she used to follow up with me and check if am interested to join CTS.

But now the issue is, i got this opportunity from CTS initially through an external consulting firm. The person used to continuously follow up with me and help me for any onboarding doubts/issues that i had during CTS pre boarding time. She responded and helped me with all the queries more than CTS hr.

This is causing a guilt feeling in me. I know it might sound silly, but can you let me know how you would respond in such a situation pls??

P.S. This is my first switch.