Follicles growing slowly

Hey everyone. My wife and I are currently on our second IUI cycle. Right now I’m being monitored every two days to see how big my follicles are growing. So far on Monday I was told my follicles/eggs were starting to grow. I heard the dr said I had two right follicles size 11 and 13mm and then when I went today it was 12mm on the right. I’m wondering if it’s normal for the follicles to grow slowly. We’re waiting for the right time to trigger ovulation. I’m praying this Friday we get good news.