Here is a quicker solution:
Command-P
Command-Control-M
and there you are...
How, do you ask?
There is a little preparation, but nothing too hard. We are just taking advantage of tools that macOS has to offer.
1) In Finder, open two windows.
2) In the first, press Command-Shift-A to open the Applications folder
3) In the second window, press Command-Shift-G and paste
~/Library/PDF Services
4) Command-Option-drag Mail from window 1 to window 2 to make an alias of Mail in the PDF Services folder
5) (optional) rename the "Mail" alias created above as "Mail PDF"
6) Go to System Settings->Keyboard, click Keyboard Shortcuts...
7) Add the Command-Control-M as shortcut to "Mail PDF" (assuming you did step 5)
DONE.
Now you can share any document as a PDF to Mail with two key presses.
Bonus: this is not just for Pages, it works across your mac.