OH MY GOD.
"Locked, cocked, and ready to rock"? Are you serious? You keep your gun in its flimsy plastic case on the top shelf of your closet and not locked up in any way, but loaded, cocked and ready to go? And you expect your 3 year-old to listen to you and to not sneak in the closet when daddy isn't watching? What the hell is wrong with you? Kids don't listen! They're kids, they don't know better for the most part! No matter what you teach them you have to still protect them!
Thank God she isn't tall enough to get your gun where you have it now, and I pray that she doesn't have any long toys to poke the case down, items she could throw up there to knock it down, or that you don't have a ladder around she could drag over and use. When my son was 4 he was fairly resourceful, I'd bet any amount of money that he could have gotten stuff out of the top of my closet without too much of a problem if he really wanted to.
God I pray I'm getting trolled. I sincerely hope with a cheesy line like "Locked, cocked, and ready to rock" and with all the "fucks" in your post that you are joking. I'd hope you wouldn't be that dumb as to trust a young child not to touch a loaded, cocked, unlocked gun in the house in a location where she could potentially get to it. It is /. and I'd think most of the people stupid enough to do something like that wouldn't be here. I really hope that's the case. If not, please, I implore you, think about what you are doing. You are putting her life and your family's life in danger.