What is your babies heart beat?

We find out December 1st if it's a boy or a girl, and after 3 boys we are crossing fingers hard for a girl. I'm 17 weeks and at my checkup Friday the baby heart rate was 154. My friend 9 days ahead of me said her baby is at 138-145 and my friend 11 days behind me is at 148. What do you ladies think?? For those of you who already found out, what is the heart rate? What were your other childrens?