How old are eggs when you buy them in the grocery store?

Excuse me, I was wondering if you could clarify something for me about the eggs that are sold in grocery stores. Specifically, how old are these eggs typically when they're on the shelves for purchase? Do they have a specific shelf life or expiration date that consumers should be aware of? And does the age of the egg impact its quality or safety in any way? I'm just trying to get a better understanding of the egg-buying process and what to look for when selecting them at the store. Thank you in advance for your help.