ANDY'S ANSWER: It's not uncommon to have a couple of noticeable growth spurts, but some boys just grow steadily instead. Don't worry just yet. You are only half way through puberty and you could easily be still adding height for another 5 years.
If you haven't had a big growth spurt yet, it could still be coming. One of my best friends was the shortest guy in class until he was 16 and then he all of a sudden just shot up like a dandelion after you mow the grass. By the time you are 18, you'll have a better idea of how tall you will end up as an adult, although you could still add on more height even after that.
There are positives to being shorter just as there are also some negatives associated to being tall. The reality is that you have no control over any of this so you're best to work on accepting yourself the way you are, no mattter how tall you end up being.