Moving to a Seated Position

This morning Luke moved to the seated position all by himself!  I was lucky enough to be there when it happened.  Luke woke up kind of early so while Mom was getting ready to for the day we had Luke on the bed with us.  There was a big bundle of sheets underneath him so he wasn't 100% on his back.  Right in front of both Mom and myself he sort of rolled onto one hip / did a sit up and to get 70% up.  He held that position by holding onto Mom's leg and with a second effort he picked up his arm and lunged up the last 30% to reach a seated position.  Mom and I were proud and we clapped and cheered for him.  Luke was also proud of himself because he was sporting an ear to ear grin.  Shortly thereafter he was on his back again and went through the maneuver one more time for practice.  If he were completely horizontal to the ground I don't know if he could repeat his accomplishment but in my opinion I think we can check off another milestone.