So, if youíre raising kids, you know as well as anyone that milestones are all around us all the time. Moments like first steps and first words and first vomit ... theyíre everywhere. And those beautiful firsts represent waaaay more than just the actual act of taking the steps or speaking the words or projectiling the vomit ó they represent growth and maturity and, above all, change. Stuff that can be hella freaky for a new parent who hasnít experienced a lot of changes yet Ö not to mention a little sad.

The reality is, most of us feel some twang around the heart region when our kids grow out of one stage and into another. And thatís just because itís hard to let go of certain phases of cuteness or sweetness in favor of other, less cute and less sweet stages. It just is. Cause most of us really wish our kids could just stay small and adorable and smooshable forever.

But our kids grow up. (Fact.) They get taller and sassier and more curious about the world around them. (More fact.) It just happens. And itís supposed to. But that doesnít mean we canít be sad about it. Weíre entitled to that. Weíve earned it. In fact, Iíve gotten massively nostalgic over the years at just about every change that my girls have gone through ó big and little.

I think thatís because the more our kids grow up, the further out of our reach they get because theyíre exposed to so many new people and experiences. And thatís tough, emotionally, when youíre the mom or the dad being left behind. And even though itís supposed to happen, it can still feel sucky sometimes when these big changes come.

Like seeing our kids evolve beyond those first firsts ó to things like riding a bike or babysitting other kids or getting a job ó can really throw our psyche into weird places. Because sometimes weíre just not ready not to be needed anymore. And toss something like a driverís license into the mix and BAAAAM ... brick to the face. That one hits you. Hard. Because now, the same kid who, on the morning of her license test couldnít find the clothes hamper to save her life, is now driving everywhere. On her own.

I mean, itís tough enough when the first kid gets their license. Thatís its own kind of crazy. But then, when the youngest one gets it, well thatís just madness. That changes everything. Because then, all of a sudden, us parents become sort of inconsequential.

Seriously, think about it. Without needing to schlep them around everywhere, a huge chunk of our time together evaporates. Like poof. Because when the teenage child isnít at school or at sports practice or with friends or locked in their room watching Netflix or doing their makeup, theyíre with us in the car. So, without them needing a chauffeur, we more or less never see them again. And Iíve realized that Iím just not ready for that time together to disappear.

But Iím gonna have to figure it out because my baby girl just passed her test. And sheís just like her mother was at 16 ... outta here. Sheís daring and confident and ready to road trip to Canada if weíd let her.

Now I know I could think of it in different terms, like This is amazing! Iím free! Now I donít have to worry about driving anybody anywhere! But Iím not emotionally wired that way. Iím the loser who always loved that car time with my kids. Like having them forget that I was driving when it was full of their friends so I could eavesdrop on all the dish I wasnít supposed to know. Or when weíd have car picnics when they were little in between school and soccer practice. Or the spontaneous trips to the mall to buy even more unnecessary makeup. Good times, all of them.

And even though it can be totally exhausting to have to drive our kids all over the world every day, for years and years and years, itís also priceless quality time we get to spend with each other.

Look, I was 16 once, so I get it ... passing that license test means a whole new world if youíre a kid. It means independence and autonomy and freedom. I remember thinking it was that first, real grown-up-level plateau that lifted me onto the adult playing field. And it felt amazing. I was fearless and adventurous and ready to drive cross-country the very next day after my road test.

But now, as the mom, it means something entirely different. It means that my baby and I donít have our 6-minute-drive twice-a-day together on the way to or from school. It means we lose that little sliver of time to talk without any real distractions. It means we canít jam together to all her crazya** Top 40 music. And it means Iím stuck with a useless extra AUX cord now that she and her sister share a car.

So yes, Libby, mommyís sad right now. And I have a small confession. When you accused me of crying on the day you got your license and I denied it, saying instead that some massive dust fiber kamikazed my eye, I was lying. Bold-faced lying. The truth is, Iím gonna miss you as my wingman. I hate the idea of having an empty seat next to me where you used to sit.

Maybe dad and I will just have to have a third kid so I can do it all over again ... or not.

ó Lisa Sugarman lives just north of Boston, Massachusetts. Read and discuss all her columns at www.lisasugarman.com. She is also the author of LIFE: It Is What It Is and Untying Parent Anxiety: 18 Myths That Have You in KnotsóAnd How to Get Free available on Amazon.com and at select bookstores.