None of the boxers we have had have been anywhere near the same size. Our baby now is already bigger than any we have had before and he is only 14months old so he still has some filling out to do. He is bigger than breed standards at this point and much bigger than our girl but his dad was really big too. Our rescue was the smallest but she had been treated pretty horribly by the time we got her which may have stunted her growth. The only thing for sure is the puppy stage lasting at least 3 years, they have all had that....I think it may even be longer than that for the boxer!