Where does the time go?

I've been thinking today how fast time flies with kids and it is almost sad to me. I realize my kids are still young but I wonder that if this relatively short time period has gone by so quickly, how am I going to feel when they are teenagers or adults and 15-20 years have passed? I look at them today and think how quickly they have grown up and how much they have changed since they were born. When I look back at pictures from a few years ago, they are just so little and young! And then the thought hit me that 5 or 10 years from now I will look back on pictures from today with the same thought. I will look at these pictures and memories with the same heart tug that I look at their baby pictures now. They are ever changing. I know they can't stay little forever and that the whole point of life is to grow but some days I just wish I could freeze time and have my babies be babies forever. Maybe it's their innocence or their oblivion to the ways of the world but sometimes I just want to keep them in my little cocoon forever. I remember my mom telling me that every stage of our childhood was her favorite. She would observe us at one stage and think "It doesn't get any better than this!" and then a year later, she would have the same thought about that stage. With each progression she found herself enjoying the moment even more and not seeing how it could get any better but it always did. And then I had a friend call me in a frenzy one day because the realization hit her like a ton of bricks that her 5 month old would never be five months old again. It would never be a moment she could have again with that child. We both lamented that watching your kids grow, no matter how young or old, is bittersweet. Nature must inevitably take it's course. Can you tell I'm a little nostalgic at the moment? I've had some good, quality time with my kids the past couple of days and it tugs at my heart a little to know that someday, these moments will be a thing of the past. So the lesson I've learned from all this is to cherish and enjoy the time that I have with them. They won't be little forever and before I know it, I'll be looking at photos of today thinking "where did the time go?"