This was my Peppa Pig for a 1 year old - but couldn't you just play up that it's a childrens TV show image & put something like

Happy Birthday to a very sepcial girl/boy who's 24 today! I think that's the tack that I would take - my daughter loves Tinkerbell & she's now 27 & that's the sort of thing I do for her - she thinks they're funny.

Shirl x