Does she have any other roosters? Sometimes if there’s a dominant one then the others won’t crow until far later if at all. And sometimes they just take longer to develop even with no other roosters.
One of mine didn’t crow until like after 6 months old. I think he might have even been 7 months. While I had others crowing at like 6 weeks old in the brooder. So it all just depends.
My 8 month old cockerel that I recently butchered still had tiny little round nubs for spurs despite being a MASSIVE bird but yet my little bantam cockerel that was only a few months older at 11 months and a LOT smaller had like half inch to inch long spurs

so it varies a lot.