I did some research on multiple sites to find their ages and this is what I came to. Also im not a fan of death in the end of books so please know, I don't believe in sad endings.

Shelley hennig as Astraea leithsdottir

She got big boobs😂

"I love you Kol. And it hurts to see you with her. I don't like it and I lost control." (Goddess Of hearts)

21 years old when turned•

Nathaniel Buzolic as Kol Mikaelson

"If you'll have me then I wish to be yours." (Goddess Of hearts)

20 when turned•

Daniel gillies as Elijah Mikaelson
24 when turned•

Joseph Morgan as Niklaus Mikaelson
23 when turned•

Claire Holt as Rebekah Mikaelsdottir (for the sake of the show Mikaelson)
19 when turned•

Caspar Zafer as Finn Mikaelson
28 when turned•

Devin Allowitz as Henrik Mikaelson
14 when killed•