How are they getting so big?

I was going to bed the other night and just looked in on my kids to see them sleeping and so many thoughts started to go through my head, but the main one was- How did they get so big?  I feel like it was yesterday they were still both in their cribs and they were so little.  Now Piper is up to my shoulders and Christian is up to my chest.  Christian will be 8 in 2 weeks and it just doesn't seem possible that it has been 8 years.  I love seeing the people they are growing into, but sometimes I wish time would stop a little!

 Piper at 3 months

Piper at pumpkin patch this fall

 Christian at 5 months

Christian at pumpkin patch Fall 2012