Wedding gifts! Already!!!

When I got home from work yesterday there was a big package waiting for me outside my door. I saw right away that it said it was from the store where we had registered for gifts. I happen to know my shower is not for another month so I was a bit confused. I wondered whether I should wait to open it to see if it was some type of mistake. Then I figured...there is no way I am going to be able to look at this big box and not see what is inside! Turns out it is from Joe's sister and she wrote a note and everything so it looks like she meant to have it shipped to the house. I'm not sure if this means she will not be attending the shower. Regardless, we are thrilled and appreciate her generosity. BUT should I have investigated first before opening? Is my impatience showing bad manners? I don't want to be rude...but c'mon...it was a big huge box with what I figured were gifts inside!