Growing up too quickly

Why is it that kids have to grow so quickly??? It continues to amaze us how muchLogan has developed in just 5 months. He is getting better at sitting up by himself. Here is a video of him playing while sitting up. He loves toys that play music and have dancing lights. Logan has also discovered his legs. He enjoys standing in his exersaucer while playing with a variety of toys. He has even figured out how to turn to get the toys that are located behind him. While playing, he always seems to be concentrating so hard on what he is doing.