The best reply when someone asks about your exam preparation before exams is an honest and confident response. You can try something like:
"I've been studying consistently and feel pretty well-prepared for the exams. Thank you for asking! How about you? How's your preparation going?"
This response shows that you are taking the exams seriously and have put in effort to prepare. It also opens up the conversation for the other person to share their own preparation status if they wish to do so. Remember to be genuine in your response and avoid bragging or being overly modest. Sharing your preparation efforts in a positive and friendly manner will likely lead to a constructive conversation.