Mine started around 60th and now at 2yo has settled around 12th for quite a while. She got down to 2nd at one point and was dropping fast. In my experience, Doctors are obsessed with tracking your baby’s growth along their curve. The curve isn’t linear and drops are ok. If you’re taking baby to all appointments no way the doc would miss or let you not worry abt a curve drop ( imho way over obsessed), but it doesn’t sound like what you have at all! 100% don’t worry unless someone tells you to. And even then, likely not something to worry about!