Exchange in the Ladies Room

Me: [washing my hands after peeing, looking in the mirror, fixing my dress (shown in previous post)]
Stranger: Oh. You must work out.
Me: I do.
Stranger: How old are you?
Me: 29
The stranger laughs (I have no idea what that laugh meant, maybe you are so young, maybe god to be 20 years younger.)
Me: How old are you?
Stranger: 49
Me: I'm a personal trainer.
Stranger: Ah.