Not suggesting that Hayley will play old Peggy. They might do it like Titanic where it was an older actress (Gloria Stuart) recounting her days when the ship went down and then it flashes back to Kate Winslet (or in this case, Atwell). And yes, we know she mourned him, but I don't see why audiences wouldn't want to see exactly what happened. Otherwise why show anything if we all know that? We know that Steve took the SSS to become Cap, so maybe don't show that too then, or anything else if you adopt that reasoning.