That is a 3/4 length mattress, and the foot area is pretty tapered.
You can still breath in a light rain or mist and stay pretty dry. There is a tab that you can use to tie off (to a tree branch, trekking pole, or your bike) to keep the netting off of your face.
If you want roomier options there are bug bivys from
Katabatic Gear that are pretty nice. I use one of those (the Pinion) for buggy summer trips. They definitely have a lot of room at the feet.
I'd again say that the tarp plus bivy combination is
extremely stormproof. I've ridden out literal hurricanes with them.
As for girls and mountaineering. The stoutest climbers I know were all of the female persuasion.