GO! And enjoy.
As a 50 something Grandmother I can tell you that I would LOVE LOVE LOVE the opportunity to take care of my Grandbaby for a week.
As Jan has already said, the healthier you keep your marriage the better parents you will be. Too many people focus solely on the children and wake up in 18 years to realize "their" relationship is gone.
GinnyG on Ravelry, I'd LOVE to be in your "friends"