Teddy Lupin would have had his 1st birthday during the school year, and Harry wouldn't want to miss it, but he couldn't just ditch school. So, what if Harry just declared it "bring your kid to school day" and carried Teddy around with him to the different classes (obviously keeping him away from anything dangerous) while everyone fawned over the baby and gasped with delight when he suddenly changed his hair. And when Ginny stops in the hallway to say hi, Teddy says "Maa" and touches her face, and she just breaks down crying.
