Breasts haven't changed much when does milk come ?

Hi everyone just wanted some advice ?  I'm 34 weeks plus 5 and wanted to know when does breast milk come ? I haven't had all that much change in my breasts since I got pregnant , I think maybe one cup size . All changes were at the beginning . Now they just feel normal and not swollen . My nipples have darkened and increased in size but no milk or leaking or anything . When does milk come from anyone's experience before ?  I do plan to breastfeed but at this stage , I'm wondering how ha ha ? I will obviously do formula if I can't etc. any advice would be great ladies X