Oh Prue was fully aware that her and Piper may buttheads more often here because Piper had taken up the mantle of the oldest sister. She'd sort of dealt with it once before here. Prue didn't expect Piper to be able to turn that part of her off, and it would be horrendously difficult for Prue to stop being that way. Especially now after going so long with only Mel being there, she had a natural instinct to protect her sister.
At the questions, Prue couldn't help but beam brightly and proudly. "I am! End of April, early May, I haven't exactly set a date just yet." Mostly because her sisters tended to keep coming and going during the planning process. "His name is Damien Thorn. As far as planning, I was actually just out taking pictures of potential places for the ceremony. We're having an outdoor wedding. And it's going to be a Wiccan ceremony." Now just came the part about telling Piper just who Damien was. "Now, I know you'll probably yell at me for this or think I'm insane, but it's not how it sounds. Damien is actually the son of Satan from the world he's from. So...technically the Antichrist. But he's not evil here. He's fighting with us against the evil here, and he's never tried to hurt me. He's a good guy."
Though Prue really was just waiting for Piper to go on and on about Cole and all the crap Prue had put Phoebe through because of that. But Cole had tried to kill them on more than one occasion. Damien had never tried to kill her or hurt her.