I know what you mean, Jasper was 11 pounds when we got him and now hes 42 and I still can't believe that we had him for 6 months!!!

But I actually couldn't wait for him to grow up and mature a bit because he was so bad, we could not walk the floor without him biting out legs and feet, even ripping our pants/socks, he has matured alot since hes hit 7-8 months, and its a real relief!