Calendar Catalogs and Templates

Having trouble figuring out birthdays and years and dates in your story well here's something that might get you off to a better start

Calendar Templates App link: https://apps.apple.com/app/id1547978418
You can design it to your own tastes and it's pretty free and easy to use.

To alternate days and years use Daydream doodler and find the white pencil you will easily be able to white it out and then find the day your month of specific years starts.
And count the months out make numbers stylish with Daydream Doodler an easy to use Sketch pad and a real fun way to sketch.