Baby chillin in my V..?!

So my friend gave me her Doppler, which my husband was hesitant for us to have bc the last pregnancy was a miscarriage. I’m trying to not use it as often as my paranoia wants me to. I really just got it because my mom lives in another city and can’t make any appointments so this way we can listen together when I see her. I’m her only daughter and first child so figured that would be special. Same with my grandmother bc I’m her oldest granddaughter and this will be her first great-grandchild. I’ve practiced about 4 times I think and the baby is always REALLY low it seems (I’m 15 1/2 weeks).... like waaaayy down there. According to the chart that comes with the kit the baby’s heartbeat should be found higher bc where it is located is more the 8 week mark, definitely not second trimester. Anyone else?!? My doctor hasn’t said anything during either of my appointments, just that the baby is growing fine. Should I be concerned at all? I do have a noticeable bump.