Hanging out alone with him tomorrow... should I step it up and really flirt?

We worked together this summer as camp counselors and I've really fallen head over heels for him. I'm not sure if he feels the same way though. During work sometimes it seemed like he was flirting but it might have been just a joking around friendly thing. I know two weeks ago he went on a date with some girl but he didn't really give us details. Now the camp is over and we've been texting a bit. He texted me first and we're planning on hanging out with the two other counselors at his house for a movie. But apparently they're gonna be later so he told me to come over early and we'll wait for them together. He says things that could be taken as flirting and he teases me a lot. Plus he's added in a few winky faces. The thing is, he's 18 and I'm 16. He's leaving soon to spend 9 months in Chile helping kids so I doubt he wants to commit even if he did like me. Should I try to flirt or let him initiate it?