Wedding in August please help.

I’m getting married this August. We have planned a beach wedding in Ajax. I was busy getting everything ready and I forgot about the makeover and hairdo. There’s only a month left and I’m confused. I booked appointment with the hairstylist and wedding makeup artist last day. My makeup artist suggested that it’ll be good if I get my teeth whitened. I haven't thought about the discolouration issue till then. I’m losing my nerves now. Wedding’s getting closer and I’m helpless. I don't know anything about this procedure. I took an appointment with a cosmetic dentistry in Ajax. My fiance told me that it isn’t necessary to get it done. But I want my wedding to be perfect. Does anyone here have any previous experience getting teeth whitening done? How long will the result last? Kindly share your views. Please help.