The Great Niece-Nudging

So my sister got married last year and now there's this adorable little kid in our family, right? Well, we were supposed to have a quiet gathering for her birthday. Instead, I went ahead and pushed her into the bouncy castle without telling anyone first. She screamed like mad, but she also laughed... which is what matters. Anyway, here's my question: Is it normal to feel this giddy doing something you know is naughty? Am I an asshole?