Nope....i wouldnt....was one of the lucky ones and have conceived twice whilst still b/f (one of those times was before AF post partum !!!). As others have said, gradually decreasing feeds, whilst not giving up, might see your body kick into fertile mode...

eta: you could give up b/f and AF still not return for 2-3 more months....giving up b/f now, doesnt mean AF will come in 4 weeks time....see how you go decreasing a feed or two.....GL !!!!