I know I need to stop comparing...😬

So the first heartbeat when I was super early in my pregnancy was 123, and since then it's been 159 and then 150ish. I was talking to a woman at work today and she was shocked that the first heartbeat was so low, like she said she'd never seen/heard one that was so low before. But that was super early, and the tech at the time said it was normal for early pregnancy, and that it would pick up as pregnancy went on, and it has. Another couple friend of ours is about 2 weeks behind us and their baby's first heartbeat was 170+, granted they were 8-10 weeks and my first heartbeat was 5-6weeks. Should I be worried??? My doctor has said I look and am extremely healthy and see no cause for concern but the coworkers reaction kind of puzzled me.