A little large for my taste, too, but that is subjective.
Where will the door go? ...or are we seeing the street side? Most couples that start with only one door either add a second one shortly, or wish that they had.
Looks a little close to the arch to me; not a lot of structural strength left at that point. Maybe move it to the right and just a touch down?

Maybe you could sell it to cover the cost of buying a pair of smaller windows, one for each door.
$.02