Is it possible to transfer an existing private world to a Realm?

I've found a way based off of this article online, which shows how to transfer worlds between devices. One of those options is using a Realm. You can just follow those instructions to convert your world to a realm, and stop there.

First, set up a new realm, and follow the text below (taken direct from article)

You will need an active Minecraft Realm in order to do this. If you have not yet used your Realms trial, you can use that to transfer your worlds. For information about Minecraft Realms and how to start a Realm, go here.

Once you have created a Realm, follow these instructions:

1. From the first device, please do the following:
2. Select the pen icon next to your Realm from the Realms list
3. Select "Replace World" and confirm
4. Choose the world you would like to transfer
5. Wait for the upload and select "Let's go!"
6. Access Minecraft from the second device and do the following:
7. Select the pen icon next to your Realm from the Realms list
8. Select "Download World"
9. Wait for the download and select "Let's go!"

All you need to do is stop after step 5. Once step 5 is complete, your world will now be a Realm!