I don't think she mentions it in the book.
Tanya was around 25 years old when she was changed into a vampire by an unknown vampire.
He was 21.
Tanya
an old vampire changed her.
Over 3000 years old. It is unknown how old he was when he was changed into a vampire.
A mysterious vampire she met in the mental asylum she was put in for seeing the future. James was hunting her and the vampire didnt want Alice to get hurt so he changed her. James killed the old vampire
A leader of a coven in London it's on page 331-332 in twilight
The vampire from the Denali coven that liked Edward was named Tanya.
She was changed into a vampire in 1920
James was the vampire that meant to kill Alice. there was an old vampire that had loved her and he changed her to protect her from James so James killed the old vampire instead and left Alice because he couldn't drink her blood. So he was determined not to let the same thing happen with Bella, he wanted her for himself.
It was Tanya but he didn't like her back.
The age of the vampire as far as physical appearance is fixed at the same age as when they were changed. Their chronological age may be hundreds of years or longer.
Tanya will be 24 years old when she is three times as old as Shawn, who will be 8 years old at that time.