Heart rate...??

Hello...so at my first app. Doctor wasn't able to find a HB but I was able to see a flicker at 7weeks prego...I am now 10 weeks and I have a fetal Doppler at home and I an supper postaive that I found the heart beat it was 171! Does that sound familiar to any of you mamas or am I just in over my head??.. it was super fast and I don't remember what my sons HB was 4 years ago but I have had 3 loses since him so I'm praying this is our healthy rainbow baby...