Will this get rid of all the data on my macbook pro (high sierra)?

No, you are simply removing one file that bookmarks a setup process has been done. Any data loss will be a result of something else (coincidence or running other commands) if you happen to lose data.

Good luck getting a new account created.

You can also set a password for the root user in single user mode:

fsck -fy /     *(optional: if you unmount cleanly you don't have to do this)
mount -uw /
launchctl load /system/library/launchdaemons/com.apple.opendirectoryd.plist
passwd root    *enter a password here. Nothing will show on the screen as you type. Press enter and enter the password again.
exit           *Proceed startup process

And then you can login to the root account and do things that require privileges.