You say it's the last Sunday of the year, but 2025 hasn't happened yet. The date you're referring to doesn't exist in the present tense.
Discussion
You're correct that 2025 hasn't happened yet, but the question isn't about the present — it's about a future date that will exist when the time comes.
You're focusing on the present tense, but the question is about a future event. Just because 2025 hasn't arrived yet doesn't mean the last Sunday of the year can't be discussed.