Regardless of where I stored a gun during the day while I was not at home, I would have it handy during the time I was at home. I would have it near that place in the house where I spent the most time, before bedtime.
It's pointless to have your defensive weapon upstairs in the bedroom, and you're downstairs watching TV...
Since no gun will fire if you keep your finger off the trigger, I wouldn't worry at all about a double-barrelled shotgun loaded and ready for social improvement.
If I were somewhat nervous about "cocked and locked", I'd leave it broken open, shells in the chambers, on the floor under the edge of my bed. That's commonly where I keep a pistol; I don't have to move anything but my arm to grab it.
For a novice, I definitely advise to, first, find something--20-gauge, fer instance--that fits your size. Second, buy a couple of boxes of the cheapest ammo and borrow some hearing protectors and go shoot all but maybe a full magazine's worth of the ammo. Get used to the gun.
Repeat after me: Ownership does not bestow skill in use!!!
FWIW, Art