Alekhine Defense-Brooklyn Variation

In the old days, I played Alekhine's Defense in postal Chess. It is fun and playable especially if you like the hyper-modern game. I have a game in progress here on Chess.com that goes 1e4,Nf6 2e5,Ng8 3d4,c6 4f4... The question here is ,"Am I playing into my opponent's strategy by advancing those central pawns?" After all, the whole point of this defense is to attack advanced central pawns (hyper-modernism in action). Commentss anyone ?