Mark those three eggs. I use a black Sharpie but other things work. Then check under her each evening after all the others have laid and remove any eggs that don't belong. There are different reasons to do this, no good reason to not do it. She may not like it but it will not hurt her. If you are worried about her pecking you, wear gloves and long sleeves.
What color are those eggs? White is pretty easy too candle, dark brown get challenging, blue or green can be hard. Have you candles eggs before? You don't have to candle except for your curiosity. I never candle eggs under broody hen but curiosity can be a strong drive.
If you decide to candle wait until it is really dark. Put new batteries in your flash light if it is dim at all. Wait at least until night #7. Do not make any dramatic decisions after a first candling. Give them time.