Can I create a child theme using a subdomain that will eventually have a different domain name once

I would like to change some php coding on a site I’m working on. But first, I would like to create a child theme so that I don’t lose the code changes when I update the theme or WordPress or both.

The site I’m working on is a subdomain (, but it will eventually be called when it’s ready to go “live.”

Here’s the question: Is there any reason that a child theme under will cause problems when I am ready to switch from to

I would use a child theme for now, except that it is currently pointing to my client’s Etsy site until her portfolio site (the one I’m working on) is ready to go.