When it comes to recipes and the size of eggs the size of the eggs actually make no difference.
When a recipe calls for 2 large eggs you would use 2 medium eggs and when it calls for 2 medium eggs you would use 2 large eggs.
Of course using 3 medium eggs instead of 2 large eggs will not harm the recipe.
I've used 3 medium sized eggs when a recipe called for 2 large eggs and all I had was medium eggs.
The recipe turned out just fine.
But the large and medium size does not really matter when it comes to counting the amount of eggs you need in the recipe.