Imagine the room finally set up, the music playing, and everyone actually showing up to celebrate. Pulling off a sweet sixteen party takes a lot of moving parts, and the venue eats up the biggest chunk of your budget right away. If you want to keep costs reasonable, timing is everything.
Booking the space for a Sunday instead of a Saturday instantly drops the rental fees. At around $4500 total, you are looking at a real chunk of change, so you need a timeline that keeps you from scrambling at the end.
Remember that the intro window is a firm deadline, not free money. If you still carry a balance when those 15 months are up, interest kicks in on the remaining amount.