Follow car seat or follow pediatrician?

So I asked my pediatrician when to move baby front facing and she said keep her rear facing as long as possible, I’ve also heard our state recommendation is at least 2 years, but I just saw on the car seat this. It says only use in rear facing when less than 22lbs. My daughter is 15 months and at least 21 lbs. does this mean that at 22 or 23 lbs I have to move her front facing? Not sure which recommendation to follow?

**edit: this is a convertible car seat. Graco Sequence 65 Convertible Carseat