Gwen Stefani: Let's Do The Time Warp

Gwen Stefani's fountain of youth is her kids ... because while they get older, Gwen doesn't look like she's aging a bit.

Gwen took her 3 boys to Disneyland Thursday -- and from the looks of it -- her eldest, Kingston, who's only 9 -- will be taller than mom in no time.

Gwen, on the other hand, has barely changed since this photo of her and King from 2007.

My, they grow up so fast ... except for Gwen.