Saying good-bye

Tonight I said good-bye to the last of my beagle puppies. After 8 weeks of being mom to these little rascals, I must say that I'm going to miss them. It's hard to let go.
My oldest son turned 15 yesterday.............................my thoughts drift to the day when I'm going to have to let him go. He's such an integral part of our family structure. I don't know how I'm going to cope with him no longer being a constant presence in this household. It is reassuring to know that he is becoming an independant, hard-working, responsible young man, and to know that he's not involved in anything self-destructive, at this point at least, but still, the inevitable departure of one of my babies is sad.
Apparently a few weeks after a mother dog loses a pup, she know longer recognizes it. I don't know that I would wish for this, but knowing that my motherly instinct will never end so long as I'm alive makes me fear for the future when my chicks have all left the nest.
As mothers,it seems as though we just start getting good at our job when suddenly we find we've lost it.