Sorry, I have no idea when female silkies get wattles unfortunately. I've read comb type and whether they are bearded or not affect the size of the wattles but not when they might get them.
Your little white baby looks like it might be non bearded, her/his wattles will probably be a lot bigger than a bearded silkies would be. Your black baby does look bearded to me though so you won't really be able to compare those two in terms of wattles to guess at sex.
Maybe someone else who knows more will chime in, I'm curious too!