I tried to rephrase it a bit to make the joke clearer.
(It's a breast joke, OK? Also it's a followup to another strip making fun of Setsuna's "I'm Gundam" line.)
Setsuna...?Hey, this person's a princessIn a 'we are' kind of senseWho!?Marina IsmailIt's been a while, Marina Ismail.Se... Setsuna F. Seiei!?You were alive after all! Ah, after four years I couldn't recognize you at a...Ah, her... she's Gundam as wellGa!?*gracefully*A princess's conduct!!A... ah... by Gundam you mean...Four years' timeBoys' Aspirations, Girls' AspirationsThat kind of...Well that's because my growth period is all over!It's been four years... You haven't changed a bit.