The werewolves don't live forever, but they don't age for a period of time, until they are able to stop fasing into wolves.
Why Are There No Elder Werewolves? One of the best things about being a shape-shifter is that you are technically immortal as long as you keep on phasing. Yet, not only are there no elder werewolves in the story, many people in the tribe, even Jacob, didn't even believe in their existence.
Jacob will live as long as he keeps phasing and he won't stop as long as Ren is alive. So technically he CAN live forever but he could also be killed by a vampire, another wolf-shifter or Ren could die by one of those and Jacob would stop phasing and die of old age.
When they phase into a wolf for the first time, they stop aging. There are plenty-a-plot-holes here BUT if Jacob maintains a regularly scheduled shape shift, he can essentially stay young forever. This is a good thing because Renesmee will be Jacob's age physically in a mere few years.
Members of the Quileute wolf-pack do age if they do not phase for a long time; Jacob's body has physically grown to the equivalent of a 25-year-old in Breaking Dawn but stops aging after that.
It is implied that Renesmee's growth will slow down until it ceases at the age of seven, by which she will have the appearance of a young woman. She may be able to live for centuries minimum, if not more.
Jacob is completely over Bella and the wolves are forbidden to harm Renesmee, because it is against pack law to hurt or kill the person a wolf imprints on - there is no exception to this of all the pack laws.
The half-vampire daughter of Bella Swan and Edward Cullen is born during Breaking Dawn, and races through her physical maturation. According to fellow half-vampire Nahuel, Renesmee be fully grown at the age of seven.
Vampire venom is poisonous to the Quileute wolves, so they would die. But Renesmee isn't venomous. Female hybrids aren't venomous in general. I think it's actually stated in the books that renesmee bites jacob lol. So nothing happens really.
Although Edward and Bella tell him that Renesmee is an orphan that they've adopted, he discovers their biological relation when he looks into her eyes (which he recognizes as his own), but decides to stick to the adoption as their public story for their safety.
Billy Black Isn't A Werewolf In Twilight
The newest generations would only transform if a cold one, a.k.a. a vampire, was near. When Jacob's father was a teenager, however, there were no vampires in the area, so the gene was dormant.
“Immortal Children” (a.k.a. Baby Vampires)
These are small children who have been turned into full vampires, meaning they will stay 5 years old (or 4 or 8, you pick) for the rest of their lives.
Amun Is The Oldest Vampire
However, readers and viewers did get to know a bit about his personality and the dynamics with his coven. Amun was actually mistrustful and paranoid, and he was especially protective of Benjamin.
Jacob is known as the physically strongest in both packs, though not as fast as Leah. In battle, he is very capable of handling his opponents.
We all know vampires are extremely strong and fast, but werewolves are faster and stronger and they have the advantage of being pack hunters - so rarely hunt alone.
He was the youngest member of the pack before Brady Fuller and Collin Littlesea. According to The Twilight Saga: The Official Illustrated Guide, Seth was born in 1992 and phased in 2006, which means that he was around 14 years old when he phased, not 15 like the series depicted.
Seeing as she's half vampire, one would think she would age much slower than humans, since vampires can't age at all. However, poor unloved Jacob shouldn't have to wait eighteen years for his happily ever after, so Renesmee grows abnormally fast, and will magically stop aging once she reaches sexual maturity.
Renesmee Cullen: a vampire hybrid. A human-vampire hybrid, also known as half-vampire, vampire hybrid, half-human and half-vampire, and half-immortal, is the offspring of a female human and a male vampire.
By imprinting on Renesmee, Jacob has imbued her with protection from other werewolves in his tribe. Prior to taking her on as a romantic partner, Jacob would first act as an older brother to Renesmee until she grew up – which won't take long given her hybrid nature, which makes her age more quickly.
At the end of Eclipse, she becomes engaged to Edward Cullen, and they marry in Breaking Dawn, one month prior to her 19th birthday. On their honeymoon, she becomes pregnant, and, due to the peculiar nature of her baby, Bella nearly dies giving birth to their daughter, Renesmee.
At the end of the story, Renesmee watches her family graduates and celebrates it at their home. During the celebration, Renesmee tells her parents that she and Jacob are having a baby resulting Edward to chase after Jacob.
So I was watching Breaking Dawn part 1 and realized Bella's pregnancy is 28 days long.
The idea of imprinting being a form of love makes it seem to young readers that love literally takes you over, and that nothing but that person should matter to you. It implies that you shouldn't like the same things that you did, and that you shouldn't be the same person that you were.
In Jacob's case, he imprinted on Renesmee — who he affectionately dubbed Nessie — when she was a baby, so no, it doesn't mean he's in love with her. Jacob just has a strong bond to Renesmee and is more of a protector and as she gets older, will be a best friend, someone who's there for her when she needs it.
While Jacob insists his feelings for Renesmee (Mackenzie Foy) will remain completely platonic until later in her life (as does Twilight author Stephenie Meyer), Bella (and most of the fandom) find their relationship to be unsettling at best.