Who needs to teach?

Who needs to teach when I have older kids to teach the younger ones? I remember when Kaitlyn was about 4 and she would drill Jeremy on his letters. "Joo Young, this is an 'A.' Say 'A!'" She's been a little teacher since pretty early on. She's continuing this tradition with Felicity. Before Lissy was even born, Kait had made her at least one, maybe two, color books to make sure she learned her colors. Now, Kaitlyn has decided that it's time to move on to letters.