Is it bad to turn down offer an alumni referred you to?

I connected with an alumni a couple of times who offered to connect me with a recruiter for an asset management summer internship who then put me in for a super day and I got an offer. I was really excited about the company beforehand(big US based bank, no international offices) but now that I’m thinking about my future, I want to work at a more global firm where I have the opportunity to move around internationally within the company.

I know I don’t have to take the offer if I really don’t want to but does it look bad on me/hurt my relationship with this alumni if I don’t take the offer after she helped me get it? Does anyone have an experience with this?