To the original poster, the only way to know for sure is to leave the gun on the kitchen table and leave your daughter in the kitchen while you go outside.
If the gun is exactly where you left it when you return, perhaps some of what you said has stuck. If not, well, shoot, she's two. Two year olds are curious. Probably best that you unload the gun first.
My two cents? Eight is the right age. My son is nine and we've been on bb guns for about a year now and are close to getting a .22 for him. My daughter is 11 and she's nowhere near ready to be around a real gun. They both know the rules and what they're supposed to do (Stop, Don't Touch, Leave the Room, Tell an Adult), and I'm fairly confident that my son would do all of that. There's no way my daughter would - she's a bit of a show off and would want to take charge of the situation and that, unfortunately, would include touching the gun. We're very safe in my house, but I worry about what would happen in a neighbor's house? Of course the job of the parent is to know where your kids are and who they are associating with, etc.
Free internet advice, worth what 'ya paid for it.