During your early years as an employee and thereafter, you’ll be asked your opinion on various aspects of the company and industry by your boss and superiors. It’s incredibly frustrating when young employees answer these questions with “I’m not sure” or “I don’t know”. Not only are you not contributing anything to the conversation, you’re also showing an attitude of disinterest.
When asked for your opinion, give it. Even if you haven’t thought of it properly, take a position and give an opinion. You reserve the right to change your mind later, but in the moment, your boss wants an answer from you, not a shrug of the shoulders.