After signing a 30-year mortgage and getting hitched, preparing to host our first Thanksgiving dinner marks my transition into adulthood.

Since I was a kid, my grandparents have welcomed us for turkey, green bean casserole and Gram’s homemade pies. I’m very fortunate to have grown up close to both sides of my family, but my grandma and grandpa live a whole 15 minutes away. Even now — after I’ve moved twice.

Thanksgiving meant getting up early with my sister to watch the Macy’s parade from New York City, the pair of us eating Eggo waffles as we waited for the day’s festivities to begin. In later years, Kate and I began addressing our Christmas cards that day — a new tradition — and pouring over the flyers for Black Friday sales.

Things have changed, of course. For one, I usually have to work on Black Friday . . . though no longer as a cashier, thankfully. (Although I kind of miss those crazy, frantic sales days at Michael’s and Borders. It was the Super Bowl of retail, you know? Everyone banding together, ordering Chinese, wearing elf hats, working until the wee hours. I really did love the bookstore.)

And now we’re married. Grown-ups. Katie is at her place; I’m at mine. Last holiday season, Spence and I were very new newlyweds — and I was stricken with this panic that we should be starting traditions as a couple, trying to parse together what we should be doing on Thanksgiving morning. Which ended up being eating cinnamon rolls and watching the parade together, which . . . still good.

Now that we have a year of matrimony under our belts and I’m staring down the dark side of age 30, we’re beginning to cobble together our own traditions. When we settled on the house in May, I was already envisioning the holidays at our new place. The fireplace! The bannisters! The entryway! In my mind, everything was already covered in greenery and twinkling lights.

In fact, one of the earliest conversations I had with my mom — as we stood in the cold, dark house in the spring — was where we’d put the Christmas tree.

(And yes, I totally knew. In the corner by the fireplace, for sure.)

Now that Thanksgiving is a little over a week away, Spence and I have been busy getting the guest room ready for his parents’ arrival and plotting the extensive menu for our family dinner. As the guest list has expanded, I offered to take over hosting responsibilities from my grandparents this year. Gram has prepared our family feast for decades . . . and I thought maybe she’d like a break.

And here we are.

I’m feeling sort of sentimental about the whole thing. Thanksgiving, to me, is still buried somewhere under those sales flyers at my parents’ house — mixed heartily in with memories of Kate and me on the couch with stacks of cards, shouting when Santa appeared at the close of the parade. Standing over the stove with Mom as she made her mashed potatoes. Later, arguing with Dad over the wishbone.

It’s arriving at my grandparents’ home only to be hit with a burst of heat, Gram bustling in the kitchen as we all arrive in coats with covered dishes. Invariably someone will begin to sweat, prompting Grandpa to crack a door. “I’ve had the oven on all day!” Gram would say, pulling out casseroles and giving us our first glimpse of the much-anticipated turkey.

In time, someone would take over carving duties. My cousin, sister and I would steal olives and cream cheese-stuffed celery stalks from the dining room table. We’d all begin fussing with serving utensils, bread baskets, folding trays. And everything would appear in my grandparents’ dining room — magic.

Thinking that I am now partially responsible for said magic is . . . a little overwhelming. I want it to be awesome. I’m still processing the fact that: a) we own a house in which to even hold such an event; and b) I’m an adult who is also responsible for cooking. Until a few years ago, my contributions to Thanksgiving were . . . to show up with a smile? (I know. Terrible.)

And now we’re talking about roasting a turkey?

I mean, I’m being a little dramatic. Nothing unusual. It’s not like I am personally responsible for feeding a dozen people this memorable meal: everyone is bringing delectable dishes and desserts, and my mother-in-law — a talented cook herself — will be on hand to help before everyone arrives. Spence is also excellent in the kitchen and will be handling the turkey and ham, so I know we’ll be fine.

I’m just feeling a little nostalgic, I guess. About tradition.

But new ones can be formed, I know. Changed, altered, added to, sprinkled with a layer of glistening fake snow. In the end, it’s really just about being with loved ones, isn’t it? Having everyone together, preferably without the aid of smartphones and FaceTime.

And the green bean casserole, of course.

Gotta have the green bean casserole.