Two days ago you turned fifty nine months old. This letter will be hard to write.

This is the second to last letter I will officially write to you. I may write to you on your birthday every year, but I may not. I have yet to write your sister a single letter, and I feel terrible about that.

Sibling difference has been a theme for me this month. The two of you continue to find your way through sisterhood. You fight. You hug. You play. Rinse. Repeat. It has been a gift to watch you two build a relationship, and it has also been a blessing to have two so very different people in my life.

I love you both. I love you differently. You are my soul, and your sister is my heart. Or the other way around. I’m not sure. It changes every day; you two occupy different parts of my body at different times. I feel you differently. There are ways I mother your sister that I have never experienced with you. And the opposite is true. But without you as my first baby and Arden as my second, I would not know any of this. It is because of you I can know her, and because of her I can love you more. I love you more, it’s true. More than I did before. More each day. More than I ever knew.

Five years old sounds incredibly big. You have grown physically, yes, but you are also at a new stage of maturity - one I cannot say I ever thought we’d reach. There were days of you babyhood that I thought would never end. There were times I thought you’d stay that way forever. But you didn’t. You’ve grown, as you should, and you are a new person every day.

Happy Fifty Ninth Monthday.