Ladies who haven't heart the heartbeat

So I'm wondering the ladies who are farther along and having heard there baby's heartbeat yet Bc of where the placenta is did it take u awhile to feel the baby as well? My last appointment was at 15w couldn't find the hr on the doppler so they did another ultrasound everything is perfect baby is growing and hr was in the 150s my doc was sure if it was Bc she was moving or Bc of the placenta so now I'm thinking I won't feel her until later too