On Tuesday, Miranda and Henry will begin a new phase in their lives as official preschoolers. They’ve been talking about school for weeks, since we visited several times over the summer. They are excited. They seem ready. We’re all eagerly anticipating their first day.

But sweet anticipation is accompanied by bittersweet nostalgia.

Preschool starts; Christine stops.

Christine has been more than just a “nanny” to Henry and Miranda. She’s been an integral part of their lives for twenty-six of their twenty-eight and a half months. She’s been more than just witness to — she’s been part of — great things. First crawls and first steps, giggling fits and talking spurts. She’s cared for them through the fun, sweet, and loving moments, through the laughing and the dancing, but also through the runny noses, fevers, diaper-blowouts, and temper tantrums.

She was there when babies moved from one crib to two, when pureed food was first tasted, when the last bottles were consumed. She was there when first teeth came in, when hair grew long enough to need barrettes or get cut. She’s sorted through clothes, through toys, through the multitudes of baby paraphernalia that accompanies twins.

She’s been privy to our low moments, and happy for our highs.

She never was afraid to ask questions, and it didn’t take long for her to feel comfortable making suggestions… hesitant at first, to be sure. Now she makes executive decisions. What to keep and what to save (do we really need all these toys?). When to give up on a failing nap. How to mete out appropriate consequences for typical two-year-old shenanigans. She disciplines with a firm hand, but doles out hugs clearly backed by true affection. I think I can safely say she truly loves my children.

Yes, she is family.

I’ve spent the past two years thanking my lucky stars that Christine responded to our Sittercity ad. And we didn’t only get Christine, we got her sister, Amy, who has filled in when Christine was unavailable. Amy, who Miranda and Henry “call” on the phone when they are playing, had never held a baby before holding mine, and now she is a pro. I feel a certain sense of pride in knowing that not only did these two wonderful sisters play a pivotal role in the beginnings of my babies’ lives, but also in the knowing that they’ve learned important skills from the very children for whom they were caring.

On Monday, Christine is going to meet us at the preschool to keep me company in watching Henry and Miranda explore their new classroom during the meet-and-greet hour, and then she’ll take them out to lunch. She’ll bring them home, give them kisses, and officially end an era.

The next day is the first real day of preschool. No more hanging out at home with Mommy just in the other room. No more only having to share with each other. No more Christine-nanny-care. Welcome to the big, wide world, kiddos.

I refuse to say goodbye. Things won’t be the same, but it won’t be goodbye. Right?

Right?

Dammit, right.

(Right?)