A senior class at a Pennsylvania high school has had "double the fun" the past four years.
The graduating class of 2024 at Norwin High School in Irwin includes 11 sets of twins, according to the school's principal, Dr. Michael Choby.
"All 11 sets have been here all four years," Choby told "Good Morning America." "This is my ninth year as the building principal and this is for sure the most [twins] we've had in my nine years."
Norwin High's graduating class has just over 400 students, according to Choby, which means twins make up 5% of the graduating class.
Nationwide, twins occur in just around 3% of all births, according to the U.S. Centers for Disease Control and Prevention.
Choby said it was a faculty member -- who is also mom to one of the sets of twins -- who put together that the 2024 senior class had an abnormally high number of twins.
One student, Gianna DiPerna, who with her twin sister Gabriella DiPerna is part of the senior class, said she realized the phenomenon her sophomore year, when she had five sets of twins in her gym class.
"It's comforting to know that there's so many people that also share the same thing," Gianna said. "It's really nice to know that like, in each class, there's someone that's been on the same path as you as far as siblings go."
MORE: Couple welcomes 2 sets of 'rare' twins 14 months apartSome of the sets of twins have been in school together since grade school, including Gianna and Gabriella and fellow twins Anna Beresnyak and Bella Beresnyak.
"It's like having almost like a built-in best friend," Bella said of her experience as a twin. "Always going to school together or just walking in the halls together, even if we don't have the same classes."
The twins in Norwin High's senior class include a mix of fraternal and identical twins who contribute across the school, according to Choby.
He said there are two sets of twins who are especially hard to tell apart, proving the occasional challenge for teachers and administrators.
"It's a very wide range of students, which is a phenomenal cross-section of our student body," Choby said. "Some of them go to our current technology center, some of them are in orchestra, some of them take some of our most challenging Advanced Placement courses, some are in the theatre department, so it's a great representation of the unique skills of Norwin High School."
Gianna and Gabriella said they both play in Norwin High's orchestra, and they plan to attend the same college.
"The twin bond is just something that, you know, most siblings don't get to have," Gianna said. "But I'm very grateful that I was able to have this twin bond throughout my whole school experience."
Anna and Bella, meanwhile, said they plan to attend separate colleges that are about two hours apart.
"When we were little and we were in the same class together, it was nice because she'd have me and I'd have her to bounce off of each other," Anna said. "And now, it's kind of funny as we get older, seeing how we are very different in both personality and what paths we're going on after high school."
MORE: Mom who was expecting daughter shocked to welcome twin sonsAt Norwin High's graduation ceremony on May 24, all 11 sets of twins will have one last chance to experience a milestone together.
"Realizing that there are other sets of twins in our grade, first of all, is crazy," Gabriella said. "I just think it's really amazing that there are so many of us graduating."