Could it be any less plausible than how Diana/WW went 67 years without aging at all? I hope it's not another cryogenic freeze thing... that bs has been played to death. On a side note, Gal Gadot sure does look the part.
First, agreed on Gadot...she's a smokeshow.
As for WW aging you have to realize she's a demigod. Unless I'm terribly mistaken she's a daughter of Zeus so anything close to normal rules aren't applying.