Low fetal heart rate but midwife says everything looks good?

I know, I know. My midwife says everything looks good, but I can't help but be concerned. I am 9 weeks 5 days and I had my first appointment two days ago (at 9 weeks 3 days). She said everything looked good and baby was measuring a day ahead. The heart rate is what concerns me. It was 132 and with my first it was 170 at 9 weeks. I know I shouldn't Google but a lot of sites said different things. Most report that babies at 9 weeks are considered to have a normal heart rate between 155-195 (with an average of 175). Are there any factors that could lead to a healthy baby having a below average heart rate? The appointment was early in the morning, so maybe that's why? Sorry if this post is annoying to anyone, I am just afraid to pull my midwife away from helping other moms throughout the day for my little question. Thanks mamas