A nervous wreck before gender determination ultrasound. Any tips?

I'm going for my gender determination ultrasound on Tuesday 16 August and I'm a nervous wreck right now. I have two boys and I'm have no feeling what it might be. Obviously we all at home want a girl but every time I look at my boys my heart fills with love so I know another boy will be welcomed with open heart though I am worried my initial reaction might be awful. I'm thinking I will ask the tech to write the gender on a piece of paper and I will look at it once I am alone. Is that a good idea?? By the way my husband and boys have no clue that I am going for an ultrasound as I was thinking of giving them a surprise later that night!!