GUYS! HELP! I'm giving myself a mini makeover.. Tell me if you think this will look good?

I'm a 20 year old female. I'm white, i have fair skin and I have long, fake (extensions..but they look like my real hair) brown hair. I want to dye it black. My boyfriend's army graduation is coming up and i want to look amazing. I'm 120 pounds, and I have a fairly good figure in my opinion (big ***) so I'm getting a tight dress and a few cute new outfits for the couple of days I'll be up there. I even tried some new makeup and it looks great..so all that's left is this decisions about my hair. I want to dye it black, Katy Perry looks hot and she has black hair. Guys, what do you think? I've had brown hair for a while and dyed it black a while ago, then changed my mind. I would love some helpful advice. I think with a tight *** dress on, some awesome heels, freshly whitened teeth and this new black hair I will look fantastic. Yeah?