What do you wish someone would have told you before you started this career?

If you are happy with the career line you opt for yourself then your answer should simply be like - “I wish someone would have told about this so earlier, so that I have achieved more by this time here”

If you are not happy or satisfied with the work you are doing, do not mention that you are not happy or you have chosen the wrong profile. The best answer here can be - “I wish someone would have told me some other available courses so that I can get more visibility in opting for my career but no worries I am planning to have some more relevant courses.”