Hey so,
what i suggest is to just pick randomly,
it can be 22 x 22 too !!! and experiment!!
But make sure that your code can use multiple sizes of tiles so that
like
just changing a global variable changes the size of tiles everywhere in your events
so that once you explore your game
and decide you want to change
and the change is because
you actually spent some time and got experience
you can do the change with ease