I assume it will be possible one day. Supposedly iOS 10.3 automatically converts the file system to APFS. When or if Apple will do that on the more complex macOS is unknown.
Why the big rush to APFS anyway? On the Mac, it is still in beta and will be for some time. You would lose more features than you would gain.
If you really, really want to use it, you can reparition your internal drive, setting up one partition as APFS and moving your home directory there.
But I strongly suggest you do not attempt to use APFS in any fashion until you get a backup drive. I strongly suggest you do not attempt to use your Mac at all until you get a backup drive.