4 month doctor's appt

Grayson had his 4 month doctor's appointment last week. I can't believe he is 4 months old already! Anywho, he was 16 pounds 6 ounces (80th percentile) and 26.75 inches (96th percentile). Where did this big baby come from? I still can't believe how big he is. His development is great. He is constantly rolling from his back to his belly, has great hand to mouth coordination and loves to stand up. As for his social/verbal skills he is also doing great, he turns his head to look at noises (especially mommy's voice), smiles at friendly people and it starting to become more verbal (says "ahgoo"). The Dr. thinks that he might be teething (swollen gums), we shall see.