Abit curious what people think happens, or actually how time affects you in this world. Forexample, entering places like portal stones or the ways, where time can slow, or go faster. How does it affect a human being. I mean ofc its relative to the outside world, but your body should still age normally right? Would it forexample be possible to enter a portal stone, live there for "30 years" and then when you come back out, it actually only have gone 15 years in the real world and you earnt 15 years in body age compared to everyone else.

Yes.  Moghedian was afraid of something similar when she found out she'd been held in a vacuole.  She worried that when she got out she would find the world years advanced, and already under the Dark One's control.

Ah k, i guess the reverse would be true aswell then.

Entering portal stones?  More accurately: using portal stones to enter other worlds.

The inside of a portal stone I imagine would have the same timescale as the world it exists in.

 

The time in the other worlds probably would affect the rate a person ages; given that the other worlds are safe enough to live in.

 

Though one exception might be Telaranrhiod.

Maybe also the world of the Aelfinn & Eelfinn.