Avoiding the Benko Gambit with 3.Nf3 (please help me analyze!)

I am a 1.d4 player who has struggled against the Benko Gambit for quiet some time.  Avoiding it with 1.d4 Nf6 2.c4 c5 3.Nf3 has been working for me lately.  Please help me analyze my round 7 Commercial Chess League of New York win:

 I've never played d4 so not familiar with this opening, but 3 d5 would be my instinct and take the gambit. Something like this

1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5 a6 5. bxa6 Bxa6 6. Nc3 d6

IMO white is ahead.

point of the benko gambit is that black ends up with a lead in development and a  lot of counter play on the queen side, this often lasts well into the endgame.. with either qb6 or a5 and moving over the king side rock..

white wants to support the d5 pawn with nf3 and e4.. e4 isn't normally played until the kings bishop is played to g2 or white risks black swapping bishops and ruining the castling position..

Once castled and with the queen on b6/, bishop on a6 and nf6 -> ne4 black can also put a lot of pressure on f2 especially if white has moved the rock to e1 to try and support an e4 pawn push or attack. Black also fianchetto's the kings bishop and can move the bishop into d4 supported by the c5 pawn..

certainly its one of my fav lines as black