Lourd appeared on "The Ellen DeGeneres Show" Tuesday and said she was fortunate to appear opposite her mother, Carrie Fisher, in those two films.
"It was incredible," Lourd said. "I'm a big believer in things happening for a reason, and I think I ended up in that movie for a reason."
Fisher died last December and the next day her mother, actress Debbie Reynolds, died.
Lourd called them "goddesses" and said it's been difficult to express her feelings since they passed.
"If I say I'm doing good, I'm too happy, and if I say that I am not doing good, then I am a mess," she said. "It's, like, really hard to know what to say about it because it is just so surreal and impossible to deal with."
Fans can see Fisher in the new "Star Wars" film due out December 15.
Lourd said she was actually up for a starring role in the new "Star Wars" franchise.
"J.J. Abrams called me to come in for 'Star Wars' because he couldn't find someone for the lead," she said. "He ended up finding Daisy Ridley, who's an incredible actress, so talented."
It was the first role for Lourd, who said her parents (dad Bryan Lourd is a talent agent) didn't want her going into acting.
"I was super excited," she said of landing her part in "Star Wars." "I didn't know what was going to happen and ended up going and fell in love with it.
That led to "American Horror Story" creator Ryan Murphy urging her to read for him for his new series "Scream Queens," Lourd said.
"I was in New Orleans a week later playing Chanel No. 3," she said. "It's so crazy."