if you barely have enough to iron, then you probably shouldnt be ironing. Altho sometimes the jump to iron makes all the difference, especially when playing civs with horse archers. HAs simply chew up CAs, and the HAs can normally win in a 5 to 7 fight (of course this is removing siege)
Not to mention that in iron there is ballistas, catapults with engineering and ballistics, etc etc, alchemy
Scythe chariots...
Basically if you have a good steady stream of food rolling in dont be afraid to iron and take the risk, cause ironing can really turn the tables on the other guys when their cavalry or camels are completely shredded by ballistas and HAs