Honestly, I would probably tell some one the same thing, if I were a BC breeder. Border Collies are like a different animal for most first-time owners! These dogs just FLOOD shelters & rescues, especially considering that they aren't that popular. On top of that, you are a young person, and Lucy isn't exactly an active working dog.
I'm just trying to say... don't feel offended. I bet if you would've kept at it, proved to her that you are an avid dog lover & have the time/passion to own an intense working breed, asked to help her with her dogs, maybe fostered a BC to get your feet wet, she probably would've sold you a puppy. It's just that the "average person" should not own a Border Collie, you have to prove you're above average!
I wish more working BC breeders were like this. Most are old-fashioned and say "well, here's your pup! enjoy." and that is the end of it.