"My love for her is not something that can be changed- it's physics, not emotion: it's the exact weight of radium. It is vast and it is exact. It is tender and finite and inexhaustible. My love for Penny is a fact. My love for her is a brutal fact about the world."
Sheldon/Penny
Childhood friends to lovers
A movie was filming in Nebraska and they needed a little girl who could play the part believably (physical farm hand stuff, riding horses, etc.) Penny got the part and fell in love with acting. She's 7
It was just supposed to be something small, but when the movie came out everyone loved her. She continued to act and was majorly successful. Like every little boys' first crush successful(Think JTT )
Sheldon Cooper is a genius, a child prodigy. He's 11 and did something amazing in Germany (I know he goes when he's like 15 or something, but I changed it)
They both get invited to a talk show that interviews child prodigies (Think Steve Harvey's show Little Big Shots)
Their chemistry together on that show is so good/funny/adorable/sassy that they get invited to appear on other shows together. They build up a friendship.
Years go by and they both go their own paths but stay in contact. Penny living in New York but traveling for work. Sheldon living in California like Canon.
Penny from years of learning about the science/nerdy stuff from Sheldon has done a few nerdy/sci-fi works that make her the crush of every nerd out there including Sheldon's friends.
One Comic Con the boys are sad that they couldn't get tickets when Sheldon reveals that he got tickets and "backstage passes" (I know thats not a thing but I can't think of a better name for it right now) for a movie panel. He got them from a friend as he hasn't gotten to see them in a while and they want to meet at comic con
Comic con arrives. They geek out. They go to the panel. Have a great time. And are about to do the meet and greet type thing. The boys are assuming that the friend will meet them back there and just focus on the fact that they're going to meet the actress they have a crush on.
They lose it when said actress hugs Shelson and calls him Moonpie