You are picturing the yard set up, the food laid out, and everyone celebrating before the baby arrives. Planning a catered party with a dessert bar takes some coordination, and the biggest lever you have is simply giving yourself enough lead time. Book your caterer three months out so you lock in your date and avoid any last-minute scramble.
A typical US event like this runs about $1500. Breaking that total down into smaller, predictable chunks makes it much easier to handle while you are buying supplies, sending invites, and getting the yard ready.
The 0% intro APR period is a deadline, not free money. If you still have a balance left when the 15 months are up, regular interest will kick in on what you owe.