Tinkerbell shows up in a lot of different cartoons on TV now and then and has done so for many years. She has not aged a day either so I guess that means than Kes will live for almost an eternity too.
Unfortunately, that's not irony and you don't know your Tinkerbell well enough to remember she was a Judas. She sold out Peter Pan, Wendy and all the Lost Boys to Capt Hook.
The irony is the fact that Kes looks like Tinkerbell, a character that never grows up and will never die but yet Kes will grow old and die over a short period of time. Kes looks like Tinkerbell but is mentally Wendy, Peter Pan's love that didn't want to be young forever and left Neverneverland to grow old and have the life she never could with Peter. Ocampa was Kes' Neverneverland. The fact that she was facing her death in "Fury", it's natural she'd want to return to the place of her youth.