Article continues below advertisementKJ Apa learned how to grow up fast after welcoming his 3-year-old son, Sasha Vai Kenet Apa, in 2021.The Riverdale star, 28, opened up during a guest appearance on the Thursday, August 14, broadcast of Sirius XM's "Radio Andy" about how his life went from partying to diaper changing following the birth of his and ex-girlfriend Clara Berry's only child.Apa explained to host Andy Cohen that he was 24 years old at the time and was at the height of his fame thanks to his success as the star of the 2017 hit high school drama Riverdale.