“It's been forever!”
It's been forever! is a familiar greeting after a long absence, whether months or years. It's been ages! has the same meaning.
B1-46 / CEFR B1 / EPISODE 46
Expressing feelings at a reunion
SceneOutside a café, Tina runs into her close friend Lena. They haven't seen each other in two years.

WORDS & CONTEXT
It's been forever! is a familiar greeting after a long absence, whether months or years. It's been ages! has the same meaning.
Bangs is American English for the hair across the forehead; British English uses fringe. This meaning uses the plural form. Tina refers to the hair she cut herself in an old photo.
Don't remind me. playfully asks someone not to bring up an embarrassing failure or unwanted memory. It usually conveys embarrassment rather than real anger here.
I should let you go. politely ends a conversation out of consideration for the other person's time. The joke is that Tina says it, continues talking, and has to say goodbye again.