5 weeks old and baby J has good head control already.
I'm a huge advocate of Tummy Time for babies, especially now that it is suggested that babies sleep on their backs until they can roll over.
I never knew Tummy Time's importance until I babysat for an infant that did not get the recommended 15 minutes a day. His play time was usually in his swing or bouncy chair or flat on his back on a play mat. And since he napped on his back, slept at night on his back, and was in his car seat a lot, too, he ended up with a pretty misshapen head.
But Tummy Time is more than just "let's keep my baby's head round" time. You can accomplish that just by holding your baby or wearing your baby in a sling while limiting their time on hard surfaces.
Its important for them to be able to strengthen their neck and upper body muscles. They'll need these for good head and neck control as well as the ability to roll over and sit up.
I'm lucky that Jocelyn really enjoys Tummy Time.