You need to do the following right away:
Remove the eggs and dispose of them.
She has not yet incubated them long enough for them to become viable.
Remove the male into a different cage.
Remove the nest box from the cage the females are in.
Rearrange EVERYTHING in the females' cage and put the cage in a different room.
Limit the daylight hours the female gets to no more than 8 hours per day.
Ensure she is getting a calcium supplement in addition to her cuttlebone and mineral block
If she lays more eggs even when the nestbox is gone, dispose of each of them right away.
You need to throw her out of breeding condition.
Following the steps I've given you will do so but she may lay several more eggs before she stops.
Please do NOT put anything in her cage that can be used as a nesting site.
You really need to do what is best for your budgies and for you to allow them to breed is putting both the 6 month old female and any potential offspring at severe risk.