One really good thing about a large enclosure right away is that you will not have to upgrade as the snake grows.
If it is a tall tank. I would make levels in it. Tree limbs, shelves ect...
I dont think the tank is too big. However the holes at the top might be. I would see how large your baby is to it. If need be You might wanna get a smaller cage (Shoe box size) for 6 months or so until he/she grows up.
Yes snakes can die from stress. However it is usually a prolonged stress, they usually will show signs of it. (not eating,bad sheds, biting,ect....) Stress can come from so many sources. From temp changes, air fresheners, food changes, mites, moving the cage around ect....Anytime you change the snakes routine or enviroment, look for signs of stress....Thats why when you bring home a snake it is best to let it be for a 5-6 days before messing with it. Let it adapt to its new surroundings.