don't worry. i had not had milk before my last delivery but i could breastfeed my 1st baby for 14 months (with constant 2months of frozen milk reserve in fridge). the hardwork (frequent feeding, no bottle supplement in 1st 3 weeks, right technique...) after delivery is more important.
no relationship between success of breastfeeding and whether there is milk production before delivery or breast size etc. don't worry. it is normal to have milk once after delivery. whether successful or not depends on hardwork after delivery. add oil!!