They don't. Bella in her head guesses their age on how they look.
They never do.. but i would say they are about 14 or 15.. from looks and the age of the actors that play them
Jane and Alec's ages are not mentioned in the book or the movie.
No, they did not ever mention their full name in the book, New Moon of the Twilight Saga.
Yes. Alec changed before Jane because he was elder to her and Jane was too young to be changed into a vampire before Alec.
Aro Marcus Caius Jane Alec
Yes, I am pretty sure.
Alec and Jane. alec can take all of your senses away from you and Jane she can burn you mentally where you stand.
Alec doesn't truly have a mate. All he has is his sister, Jane.
The names are unknown. But there is her mother,her father, and Jane and Alec which are Twins
Jane and Alec appear for a short amount of time in Breaking Dawn Part I.
Alec is Jane's twin. He is played by Cameron Bright
His name is Alec and is the complete opposite to Jane; While Jane has a painfull gift Alec has a numbing gift.