My eldest daughter entered the tween years this summer. Like so many other phases of parenting, this one caught me off guard.

Phases. You know they’re going to happen. Other parents tell you about them. You read about them in human development books (at least, you do if you’re married to a psych dweeb).

But nothing really prepares you for what a new phase will look like on your child. This is partially because how their biology hits them is unique for each kid and situation.

When my eldest was three, she developed a stutter that came and went for about a year. It was something I refused to make a big deal about despite the advice of other, older moms. First, because I was concerned that making a big deal about the stutter would cement it in her identity as a personal trait. Secondly, her doctor wasn’t worried, so I wasn’t either.

One day I noticed that the stutter appeared for a few weeks, and when it disappeared it left behind a new language tool, (such as use of multiple adjectives or subordinate clauses). “Okay,” I thought. “This is just her brain hard-wiring itself.” The stutter was, I thought, a result of her brain firing up new neural connections. It disappeared shortly after her fourth birthday. No one had ever told me that a stuttering phase might accompany a verbal explosion. It was unique to her.

Then there was the kid phase. This happens around 6-ish, when your child stops seeming like a baby/preschooler/snuggly love-bug and starts being a kid. A great kid. A kid you’re happy to know. But a kid with things to do and people to see, and who may or may not make mom and dad a priority. This is a phase where you step back, take a deep breath and watch them begin to grow in directions you never imagined. They develop interest in things you could not possibly care less about. But you fake it for their sakes.

The tween change has been different for me. I wouldn’t say that my daughter is on the threshold of puberty, but she’s definitely within spitting distance of it. It’s terrifying. Not only because of the wealth of dangers that accompany coming of age in our society, although goodness knows, that’s bad enough. It’s the anticipation of watching someone you love prepare to undergo a transformation more difficult and delicate than they can possibly apprehend.

I’ve done things to prepare her of course. She’s heard since she was tiny that the human brain continues to develop decision-making apparatus until around 25 years of age. That all the years up to then are critical to her cabeza.

She knows that women have periods wherein they bleed to shed unfertilized eggs.

These factoids come along with more dogmatic platitudes: “School first. Then you can worry about boys.”

But the thing the tween phase didn’t prepare me for is this. When I look at my daughter, I feel like I’m mothering an infant again. Not that she is dependent on me. Rather, it’s that sense that you get as a new parent. That part of you that says, “My god, this human being is beautiful and precious and her life has tremendous potential and that is a TON of responsibility. How do I not screw that up!!!”

Part of it is that she is truly a beauty. I’m not just saying this because I’m her mother. She’s a knock out in the making.

But she is beautiful beyond just the beauty of her features. Hers is the beauty of becoming. Sharing a house with her is like living with some mythic animal that is dangerous and beautiful, and entirely innocent of both. Sometimes when I look at her, I see the fat-cheeked, extroverted toddler that flirted shamelessly with strangers, and sometimes I swear I can see the long-legged, thin nosed, driven woman she will be in a few years.

Before becoming a parent, there’s no way to understand how fiercely you will love your children. You love them so much it’s scary. So much you feel like it will break you in two. So much that you want it to break you in two if that’s what they need from you.

It’s a conflicted love. You want them with you more than anything in the world, so you can keep them safe and share their every experience. But you want the world for them too, as imperfect as it is. A world far beyond anything you’ve ever experienced, full of opportunities beyond what you could ever provide.

So you ease them out into that world a little at a time and feel them slipping away, little by little. Until one day, the weight shifts by just a fraction, and they are more gone than here, leaving you to rejoice for the new adventures they’ve found, while your own heart breaks and mends and breaks over and over again endlessly.