My son’s having a growth spurt this week, and overnight he stopped fitting into his newborn-sized footie pajamas. He’s a very tall boy, and has been pushing the lengths of the one-piece outfits for awhile, but it still came as a sad shock. My son will never fit into newborn-sized pajamas again. He’ll never again be that tiny.

People keep telling me to enjoy every moment, because it’s so fleeting. It’s the one piece of parenting advice that I always take seriously (though I’ve been given a lot of other very helpful tips). I think a lot of parents go into the experience of first children thinking that there might be a second chance for those special moments of first smiles, first laughs and first words. After all, even though there has been an upswing of only children, most people in the United States have siblings, and I don’t see that changing anytime soon.

Contrary to that norm, I’m approaching this experience as if I’m never going to have another child. It’s possible that I won’t (sorry, grandparents). I like the idea of having one child to focus on and nourish instead of splitting our attention between two. I like knowing we’d have more money to take our son on exciting vacations, give him enriching learning experiences and buy him expensive musical instruments. And I don’t really buy the argument that all children need siblings to play with. I could never imagine life without my sister, but not all siblings are as close as we are. My best friend grew up an only child and is one of the most self-assured, well-adjusted people I know. That’s what friends are for.

Not to mention that I didn’t enjoy being pregnant at all. I was sick a lot, and I never got comfortable with the fact that my body was not my own.

But I also “never say never” about the future. I didn’t know if I wanted children in the first place, until something changed and I realized I did. I don’t assume that my present self has the amount of wisdom and insight that my future self will, and therefore I don’t try to make decisions for her.

What I do know is that if my future self decides not to have another child, I want to know that I didn’t squander the special moments with my son. So I’m extra mindful of living in the moment, knowing that it might be the only chance I get.

I think that’s a good way to live life.