Goldman Sachs Operations full-time offer VS. AT Kearney Internship

I’m a graduate from a top 40 school in the world. I got a full time offer for GS Operations. It says it’s trading derivative middle office. I have alr signed the offer, meaning I may get blacklisted if i rescind. On the other hand, I have a AT Kearney Internship offer that I have not signed. If my internship performance is good, I will get converted to full-time. I’m just here to get opinions...