back again

it is 11years later and Dipper and Mabel are 23 years old and now they are back in gravity falls and then one day they with Pacifica and candy and grenda they we're shown a bright light that changed them forever , it made them unable to age beyond the age they are now making them not die , and then they decided not to tell anyone and they meet 2 guys who are also immortal and unable to age and are 24 , the adventure just started