Most known as Penny from The Big Bang Theory, actress Kaley Cuoco (born in 1985), appears in this movie with 15 years old and a blue bikini. Kaley used to have a slim and delicate face and a sexy look in Growing Up Brady (2000).
Note: the videos are without audio.
You can see the scene here:
In this second and third videos, the teenager Kaley Cuoco is in two kissing scenes. Her character was Maureen McCormick.
She really looks very young.
Video 3: