How to schedule iMessages in iOS 18

I’m on a winning streak with being the first person to wish my family and friends a happy birthday since iOS 18 came out. How do I always remember to send a message at midnight on the dot, you ask? I don’t. Most of the time, I’ve been peacefully passed out for a couple of hours already when that cheery message goes through. I don’t lose sleep, and my loved ones think I’m just that considerate and punctual.