I dont know how to explain my feelings to him

First off, I love my boyfriend, hes usually the most supportive person I have. But i recently told him I'm going to start training to become a police officer, were not out of high school yet and I know it was dumb of me- but I had never brought it up before. I've been considering it seriously as an option since I could comprehend what it was, he hasn't been very supportive, I sprung it up on him on Christmas eve and hes been super worried about it. I never wanted to bring it up because another family member wanted to be a cop and I didnt want to take away from them. This seems like more of a rant than a question, but if you have advice I'd love to listen