Teeth?!?

Sarah already has her 2 bottom teeth in. I didn't even notice her first one coming in and within a week the other tooth had popped through and now they're both visible! I swear J's took a month to get to a point where you could see them when he smiled.
She just turned 5 months and I realized the other day that she's quickly approaching an age that I love - 6 months and up. Usually by 6 months, babies are sitting up and playing with toys on their own. I'm looking forward to that. I wouldn't say Sarah's lazy...she's just laid-back. She'd rather put her hands in her mouth than reach for stuff (she does reach for things, her hands just end up in her mouth instead), and she's working on sitting up. She's only rolled onto her tummy a couple times...she just doesn't seem interested. But she is growing - I've moved her into 6-9 month clothing!