Gender prediction help

Tori • live life to make yourself happy
Ok so today I had another appointment and I heard my baby's heart rate and the doctor told me it's exactly 150. Now my great gma says the higher the heart rate the higher chance of a girl..now I Dnt remember my son's heart rate..but maybe some of you can help..my family thinks I'm having a girl but I feel like it's a boy..what do y'all think?