I wasn’t expecting to bond with my teenage son’s girlfriend over horror movies. We go on double dates.

Raising teens — I also have a daughter — is mostly about learning as you go, and since my son is my oldest, that’s been even more true with him. It hadn’t occurred to me he’d date someone who shared his interests until the first time he mentioned his now-girlfriend to me. He’d watched a new-to-him horror movie because she suggested it. My ears immediately perked up, and a few months later, when their friendship turned into something more, it was unsurprising.

Now, they’ve been an official couple for several months, and my husband and I often go with them on double dates to grab dinner, then see a new horror movie at our local theater. The ritual has provided us grown-ups with a fun way to get to know our son’s girlfriend better, and it’s a win-win for all of us (except my husband, who doesn’t love horror movies but is a good sport). Without this shared interest, I’m sure we’d still occasionally do things together, but the hang-outs would happen less often, and they might not be as fun.

My son had dated previously, but had far less in common with the person. As a parent, I saw that quickly brought an end to the relationship. Now, I’m thrilled to see him in a relationship with someone he relates to so deeply — yes, in their love of movie genres, but in lots of other ways, too. As parents, we just want our kids to be happy and healthy, but there have definitely been some unexpected perks to my son’s girlfriend sharing interests that I care about, too.

In addition to dinner-and-a-movie date nights, we’ve traveled together to attend horror events like Halloween Horror Nights at Universal Orlando Resort and Scaradise, a fan convention for horror enthusiasts. Whether we’re planning our outfits for a spooky event or deciding which restaurant to meet at before a movie, the shared interest has given me something to connect with my son’s girlfriend over, and it’s been incredibly fun.

Both my 17-year-old son and my 15-year-old daughter are pretty amazing individuals. When I held them as tiny babies, I remember worrying about time passing quickly and them growing into teenagers in a blink.

It’s gone fast, yes, but new-mom-me was unprepared for how my heart would swell with pride when observing the incredible almost-adults my husband and I have raised. I often say having teens is even more enjoyable than raising babies, and I truly love watching my kids grow up.

While I’m still their parent, I see my kids turning into grown-ups that will one day be my friends, and it’s truly a thrill. I wasn’t prepared for how much fun it’d be for my kids to start dating, but seeing them build relationships with equally cool people that I also like to spend time with is like gaining more kids — an unexpected perk of raising teens.

There are a million reasons I’m grateful for my son’s girlfriend: she cares about my kid, is talented and kind, and has helped him grow more mature as he navigates his first serious relationship. But beyond that, I love having another scary movie buddy to drag along with me to movie theaters and scary events; it makes life even more fun to bring her along.