Okay so Ive had luna since she was 6 weeks, she will be ten weeks on monday. She had her second set of shots and deworming on tuesday and today she had tapeworms in her poop. Took her back to the vet and they got her oral meds for it. The doctor said it takes weeks for tapeworms to show up but the breeder I got her from had her dewormed as well, I have the paper work for it. Is it a possibility that the breeder didnt have her dewormed for tapeworms because my vet says it takes weeks for tapeworms to show up?

I think the deworming they gave her this time is what made them show up...they were being expelled from her body. Not sure about the breeder.

Not all wormers are the same and some don't kill tapeworms or don't kill both types of tapeworm. So it is entirely possible the breeder did worm them but with a wormer that doesn't cover tapeworms or your pup could have picked them up between the time you got her from the breeder and now. I would guess that the wormer from Tuesday is why you're seeing them now like Roxy suggested. Either way I wouldn't look too deep into it, dogs get worms and it's a simple fix, end of story.