For all the mom's with dopplers!

I've been lucky enough to hear my baby Heart beat on our Doppler since 10 weeks 4 days and every day since. I'm 12 weeks 5 days and today I found the baby's HB but it took longer and was fast at 154 but was super fant, like as if it was wayyyy back there! Just asking if this is normal. Could the baby be further back? It was so faint I could barely hear it but I obviously knew what it sounded like.