Alright, let's dive into the Upside Down and figure out how old our favorite Stranger Things characters are, season by season. Grab your Eggos, it's gonna be a wild ride!

Season 1: The Kids Are Alright

Meet our core crew in Hawkins, Indiana, 1983. Eleven, our telekinetic heroine, is around 12, but who knows with her mysterious past? The Byers kids, Mike, Dustin, and Lucas, are all 12 too, making them the perfect age for bikes, forts, and saving the world from monsters.

Fun Fact:

Millie Bobby Brown (Eleven) was just 12 when she auditioned, making her the perfect age to play a 12-year-old. Spooky, right?

Season 2: Growing Up, Sort Of

It's a year later, and our gang is still 13, but Eleven's back, looking a bit older and wiser. Nancy and Jonathan are now 16, and Steve's a cool 17. Meanwhile, poor Will's stuck in the Upside Down, not aging a day. Lucky him?

Fun Fact:

Finn Wolfhard (Mike) and Gaten Matarazzo (Dustin) had their first shave for this season. Talk about growing up!

FEMAIL looks back at how the Stranger Things cast have changed | DailyFEMAIL looks back at how the Stranger Things cast have changed | Daily

Season 3: Summer of Love and... Aliens?

It's the summer of '85, and our kids are now 14, except for Eleven, who's still 12-ish. Nancy and Jonathan are 17, and Steve's a mature 18. New kid Robin is 16, and her crush, Jamie, is 17. Meanwhile, Billy's 17, but who's counting when he's got a mind-control slug?

Fun Fact:

Caleb McLaughlin (Lucas) grew a whole foot between seasons 2 and 3! Talk about a growth spurt.

Stranger Things: Then and Now I Season 1 to 5 - YouTubeStranger Things: Then and Now I Season 1 to 5 - YouTube

Season 4: The Kids Aren't Okay

It's 1986, and our heroes are officially teenagers. Eleven's finally 13, Mike, Dustin, and Lucas are 15, and Nancy and Jonathan are 18. Steve's 19, and Robin's 17. Meanwhile, poor Will's still 13, but at least he's back in Hawkins.

Fun Fact:

Noah Schnapp (Will) and Sadie Sink (Max) are both 17 in real life, but they play 13-year-olds in the show. Talk about good genes!

So there you have it, folks! Our Stranger Things family grows up right before our eyes. Well, most of them. Now, who's ready to binge-watch and marvel at their ever-changing faces?