Editor's note: This article was originally published on Amy Wruble's blog, Carriage Before Marriage. It has been republished here with permission.

Dear Daughter,

"You're my favorite person in the whole world" is not something you're going to hear me say anymore. Not only is it unfair to Daddy, but it really won't go over well with your baby sister, once she's born and learns to talk. For now, though, it's hard not to keep thinking it.

You, you, you. You're the one who burst my heart wide open. You taught me what wild, uncontrollable, unlimited, unconditional love feels like. You changed everything. You turned me into a mom.

And even though you will no longer be my only child, or even my only girl, you will always be my first.

You're the first one to make me forget myself. You're the first person I ever said "I love you" to more than ten times in one day. You're the first human whose temperature I took, whose nose I wiped, and whose projectile vomit I was too tired to clean up and just sort of slept in.

With you, I made my first-time mom mistakes, like letting you roll off the bed onto the floor. Who knew you could roll? Thank you for not getting hurt and also for not holding a grudge.

Our baby's coming soon, and while you may not be my only child any more, you'll probably be the only kid who knows what it's like to have my undivided attention. Because how do I ever stop myself from thinking about you?

This realization gives me the guilts, but then again, your sister will have some advantages. I can't imagine she will ever be bored or lonely for long-not with you and your unlimited repertoire of songs, dance moves, costumes and magic tricks. I can't wait to watch her watching you.

You. You were my first newborn, infant, toddler and preschooler and the one who continues to surprise me every day. You're the intrepid explorer who pulls me by the hand into the future. You're in all my thoughts and dreams, and every wish I make upon a star.

So when you're feeling frustrated that I'm nursing your sister instead of playing dress-up, or that I might use stern words with you but not her (she's just a baby), or that I can't stop talking about how cute she is (I like infants the way you like ponies), know that there is more than enough love for both of you, because of the ever-expanding place in my heart that you made.

You, you, you. You will always be my first.