It was 26 years ago when school first went into session at West Beverly High, introducing the world to the privileged kids of “Beverly Hills, 90210.” Of course, those who were watching when the show premiered back in 1990 may remember that the students of West Beverly didn’t look like your typical high schoolers.

Instead, they had a vibe that seemed a bit too old to be hitting Algebra class or having lunch on the quad. That’s because, for the most part, they were.

Of the Season 1 “90210” cast, only one of the students was actually age appropriate to the grade they were in. In the first season, most of the gang were high school juniors, with David Silver (Brian Austin Green) and Scott Scanlon (Doug Emerson) as the lone wide-eyed freshmen.

Given their grades, the juniors should have been 16-17 years old, while the freshmen were 14-15. How close did the actual casting get? Take a look at the cast of “90210” Season 1 below, from oldest to youngest.

Gabrielle Carteris (Andrea Zuckerman) — 29 then, now 55

gabrielle carteris 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

Believe it or not, Carteris, who played quirky newspaper editor Andrea, was the oldest member of the cast at 29 years old when the series premiered. That’s a full 12 years older than a high school junior should be. She lasted as a series regular through Season 5.

Ian Ziering (Steve Sanders) — 26 then, now 52

ian ziering 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

Steve Sanders, son of “Harley House” star Samantha Sanders, was also far too old for school. At the time of the show’s premiere, Ziering was 26. He’s also one of only four main characters to stick with the show as a regular for all 10 seasons, meaning he was 36 by the time all was said and done. Today, at 52, you can see him battling shark-infested tornadoes.

Luke Perry (Dylan McKay) — 24 then, 50 now

luke perry 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

When “90210” premiered, there was quit a bit of swooning over Perry’s coifed hair and his character’s devil-may-care attitude. Still, the man an army of tweens had crushes on was actually 24 when the series debuted. Of course, given the crazy life Dylan lived — complete with a dad that had mob connections — he always seemed way beyond his years.

Jason Priestley (Brandon Walsh) — 21 then, 47 now

jason priestley 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

If anyone battled Perry in the hair department, it was Priestley. The two were clearly the breakout stars of the show, as far as the boys are concerned. And while they played the same age on the show, Priestley is actually 3 years younger than Perry, essentially making him the David Silver to Perry’s Dylan. And nobody wants to be the David Silver.

Shannen Doherty (Brenda Walsh) — 19 then, 45 now

shannen doherty 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

While Brandon and Brenda were twins on “90210,” producers didn’t even cast actors that were the same age. Instead, Doherty was 19 — playing 17 — to Priestley’s 21. She’s definitely closer to the right age, but still too old to be a junior.

Jennie Garth (Kelly Taylor) — 18 then, 44 now

jennie garth 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

It takes this long to get to someone who was actually an age where traditionally you would be in high school. That’s five of the nine high schoolers that were actually too old for the school they were supposed to be attending. That said, Garth still doesn’t make the cut. At 18, she should have been a senior during the first season of the show.

Tori Spelling (Donna Martin) — 17 then, 43 now

tori spelling 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

At long last, someone who was playing the right age. And all it took was casting the creator’s daughter to play her. Spelling was a junior in high school playing a junior in high school — imagine that!

Brian Austin green (David Silver) — 17 then, 43 now

brian austin green 90210 (Really) old school: Recounting the ages of the Beverly Hills, 90210 cast

And it’s already all messed up again. In Season 1, David was a freshman, whereas Green was the age of a junior. He was also a nerd, who became a DJ, a musician and a number of other things. Oh, he also managed to have Donna — an upperclassman — as his very long-term girlfriend. So clearly there was a lot about this character that was unrealistic.

Doug Emerson (Scott Scanlon) — 16 then, 42 now

What’s what? You don’t remember Scott? Let us remind you. He was David’s best friend and a fellow freshman. He was one year closer to being the right age but still missed the mark. Not that it mattered all that much because Scott was reduced to a recurring star in Season 2 before he accidentally shot and killed himself while trying to look cool playing with a gun. We love you Scott, but you kind of brought it on yourself.

Posted by:Chris E. Hayner

Chris E. Hayner is equal parts nerd, crazy person and coffee. He watches too much TV, knows more about pro wrestling than you do and remembers every single show from the TGIF lineup. You may have seen him as a pro-shark protester in "Sharknado 3." His eventual memoir will be called "You're Wrong, Here's Why..." TV words to live by: "I'm a firm believer that sometimes it's right to do the wrong thing."