It has always amazed me how quickly a baby grows. When my son was born he was a big baby. He weighed 9 pounds and 12 ounces and was 22 inches long. Even though he was a large baby, I was still shocked to find out he was already up to 11 pounds by his 1 week checkup! Then later on, at his 3 month checkup, he had grown to 26 inches long and weighed a whopping 16 pounds. Now he is a teenager and is of average size compared to most teenage boys his age. As fast as he grew when he was a baby, I would have guessed him to be over 6 foot tall by now.