What does "wind up" mean?
"Wind up" means arrive or end up in a specified state, situation, or place. In this sentence, Jack says "Where I'm gonna wind up." Wind up in this sentence means where Jack's future location is going to be. Where he is going to arrive or end up. Jack isn't sure what his future is going to be and isn't sure where he is going to end up, so he uses the phrase "wind up" because he isn't sure where he will be in the future.