Google Calendar – Mark a Guest as Organizer

It turns out that the "Yes / No / Maybe" options are not initially shown for an event until you add a guest other than yourself.

If you just add yourself as a guest, nothing happens. When you add the first guest other than yourself, a guest list appears with two guests (yourself as "Organizer", plus the guest you invited). The presence of the guest list causes the "Yes / No / Maybe" options to appear at the bottom of the event's popup card and on the event's details page.

So, here are the steps you can take to create an event that you can mark "Yes / No / Maybe":

1. Create the event.
2. Add a guest other than yourself.
3. Save the event.
4. Open the details for the event again.
5. Delete the guest you just invited.
6. Save the event again.
7. At the bottom of the popup card, the "Yes / No / Maybe" options will now be available.

Unfortunately, step 3 is required for the guest list to remain; if you don't save, it will disappear. To avoid bothering someone with a random invitation, you can use a dummy account as the guest or choose "Don't send invitations" when you save in step 3.

I have done this many times, though only on Android. When you make a new event on Android, you go to Repetition and then type of repetition and then choose monthly, where you can specify a number day.

Edit: I just checked the desktop version for you, which works as well. When you make a new repeating event, first set it on the start day, then check the Repeat box, choose a Monthly event, and the option to make it a specific day is a radio button.