I doubt it, since neither of them seemed particularly happy about the idea of him dating multiple people. in addition, after Finn mentions a "she" PB starts to say she "didn't mention anything about g-" (sentence is cut off when they're attacked again). So... that probably means something? I don't know what.
It's issue #32 of the comic book series, and what you're seeing is Future Finn. Sort of. An enemy called the Mnemonoid ate five years of his memories, so from Finn's perspective he just woke up one day with an aged body.