I think Jaheira likes it when you call her old - Baldur's Gate 3

I think you are old

She's cute!

I am down so bad for her it's unreal

She's so used to hero worship, someone being playfully irreverent is a breath of fresh air. And she loves the chance to banter back and forth with someone witty who isn't afraid to poke fun and tease her.

Hell, making fun of her age is one of the best ways to get her out of a particular bout of Personal-Plot-Induced-Depression. She laughs, calls you a bastard, and gains approval.

banter druid

She accepts it. Jaheira is at that point in her life, "Yes, I'm old and I know it".
One thing to know about people like that, always be straight forward with them.

Jaheira approves all the jabs at her age. Someone can tease and joke with her, rather than worship her for the hero she is to the city.