Should I find out baby's sex

I have all girls. Wanted 5th baby to be a surprise, since it's the last baby bit at 36 weeks I just want to know. I was kinda disappointed when my almost two year old was another girl, but quickly got over it. I am praying and keeping my fingers crossed this has to be a boy. I go to the dr Monday to get ultrasound thinking of just easing my mind. What do you all think?