You should install the rod above the window frame in any case, How high depends on how much space there is to the ceiling. Can you post a picture? No puddling, curtains should go just to the floor or barely above it. You’d have to have them hemmed.

Agree with saypoint. If you install the drapes/curtains too low (at the window) it visually squashes the room.

Install curtains like the sketch below:

Puddling is a great way to catch and collect dust, and is something you'd have to re-arrange a few times a day, especially with pets or children around.