The first hand up in class isn’t always the right answer. Sometimes the kid who waited heard the whole question.

Speed of response and quality of response are separate things, and one is much easier to see than the other. Answering first requires only that you began forming a reply early, which usually means you stopped listening partway through. The person who waited had access to the whole question.

If you are quick, practise holding your answer until the question has fully ended, then check whether your first thought still applies. If you are slow, stop reading that as a deficiency and take the extra beat you need. A late right answer beats a fast wrong one.