That design... is something else

What the- Where did her arms go?!

Behind her back

Anyway, this is more than likely fanart.

Serena is 12

actually maybe younger

No, because Ash is like 16 so she is around there because Ash ages, confirmed by the anime itself, so yeah

bro he’s ageless

uhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh... ash is 10 and was always 10.

I think that she's 11.

https://www.youtube.com/watch?v=W6v99Ua1r9w