I have emailed myself in the past, scheduling it to be sent at a later time/date. I have even added events to my calendar as reminder of things I wanted to do/try.
I have often texted myself notes before, but I believe I figured out I could schedule message last year. And I use this often. Sadly, I am more apt to read a text than look at my calendar.
If you have apple or some other device and you do this, please write a quick post and/or comment a link, I will add here.
Type in your own number as contact. Compose message. Then choose menu in top right corner.
Choose schedule. And Time, date.
Hit send. The messages will show date and time to be sent.