Assalamu alaikum, I'm seeking some advice regarding an issue with my fast.

One of my friends is insisting that I deliberately broke my fast because I accidentally drank water 11 minutes before the time for iftar. His reasoning is that since I intentionally lifted the glass and swallowed, it counts as an intentional act. However, I’ve heard from others that if it was genuinely an unintentional mistake, then my fast is still valid. Could someone knowledgeable share some insight? I’m not sure if I need to make up this day later.