Today you are thirty one months old.

Today is also the last letter (I hope) to write you as an only child. (I hope!) by next month you will be a big sister when I write again.

Big sister. Let's talk about that for a moment. You have been insistent that the "big sister" is growing in my belly and the baby is in yours. Most people are bothered by this misconception of yours, but not me. I know you have some idea or plan or thought or wisdom.

I have some theories. All of my theories make complete sense of your theory. But mostly they tie back to the fact that you have been very clear this last month about how small you still are. You remind me constantly as if to ward off any pushing we may do towards your growing up faster than you'd like.

You have regressed in all areas this month, not in a terrible way, but in a didn't-we-just-get-over-this sort of way. It is frustrating. But, again, it goes back to the fact that you are set on reminding us of how young you still are, despite someone younger joining us very soon.

Friends often ask if you get what's going on, and I always say Yes, because you do, on some level, get what's going on, all too well. You are not oblivious. You are perceptive and tapped in, and you catch on pretty quick. Yes, you get it.

On some level I feel terribly guilty that you will not be an only child after next month. I always wished I had remained an only child, but, to be honest, I would have always felt like there was something missing had we stopped at you. You are not supposed to be an only child forever. Just for now. And soon, you'll be a big sister who was once an only child.

That's the thing with being first: You hold two hats. Sometimes they will fight for which should sit atop your head. Sometimes you'll don one with grace as if it had always been that way. Sometimes you'll throw them both to the ground and wish it weren't this way ever at all never.

And, yes, sometimes you'll be the baby and the baby will be your big sister.

Happy Thirty First Monthday.