I'm 14 and 7 months old, and I'm 5'1. My mom and dad are 5'6 and 6'0, and I've always been short and we don't know why. On the calculator, I got a 3.2. My pubic hair and testicles seem to be stage 3, but not much else does. I was hoping that I would've hit a growth spurt by now, but I clearly haven't, and it doesn't even seem to have started yet. I'm worried that I'll go through stage 3 and not grow much. We've done many tests and everything is normal except for the fact that my bone age is delayed by about a year and a half. Why am I going through puberty in stage 3 but am not growing? Should I expect to grow faster?
Each stage lasts about 2 years, roughly. You've crossed the line into stage 3 and it is during stage 3 that you grow rapidly, but it doesn't happen instantly. Think about a car. Even a fast racing car can't go from a slow pace to 60 mph instantly. It has to accelerate. Different models of cars have different top speeds, but they also have different rates in which they accelerate. Your body is gearing up for faster growth, but you won't notice it until you are already growing faster. For some boys "faster" means a bit faster than usual, for other boys it means having to buy new pants every couple of months for a while. Generally the slower paced boys grow "faster" for a longer period of time than the really fast growing boys.
I don't know how it will be for you in particular. There are too many variables involved. What I can say is that by the time it is all done, you should be at least 5'9". That is because boys grow to the average of their parents height or can exceed the average by up to 10 inches. Where you will end up in that range is hard to predict. Don't count on reaching the maximum, but you should exceed the minimum.