Gymnast Shawn Johnson: A true golden girl

Shawn Johnson of the U.S. in action during the Women's Artistic Gymnastics during the XVI Pan American Games, October 24, 2011 in Guadalajara, Mexico.
Scott Heavey/Getty Images

(CBS News) American gymnast Shawn Johnson was a Golden Girl at the 2008 Olympics - and she hopes to repeat that performance at this summer's games in London. Here's Mo Rocca:

Flying through the air makes her feel "like you're invincible. Makes you feel like Superman and gives you a thrill. It's like an adrenaline rush."

It's obvious that Shawn Johnson loves gymnastics, a sport she's very good at: "It's what I live for."

At the 2008 Olympic Games in Beijing, she stuck her landings and struck gold on the balance beam, and additionally won three silver medals.

Now at age 20 - young by life standards, not so young for a gymnast - she's hoping to compete in this summer's London Games.

"A lot of the kids in here are 10 - so are you kind of like the old lady of this gym?" asked Rocca.

"Pretty much. I'm the grandma," she laughed. "I've been through it and they're, like, 'Oh, she's so old. How could she still do it?'"

Special section: 2012 London Olympic Games

Johnson still does it - every morning in her hometown of West Des Moines, Iowa, under the watchful eye of her longtime coach Liang Chow.

She describes the gym as her second home: "Definitely. If not my first home. I've almost spent more time here than I do at my actual home."

If Shawn feels at home at the gym, that may be because her mom Teri Johnson has spent so much time there.

For eight years, while Shawn was growing up, Teri perched, watching - four hours a day, six days a week for eight years while Shawn was growing up.

"I kind of always felt like if I wasn't here I didn't get to see her that day," Teri said.

"We weren't hanging out, but just having her here, I felt connected," Shawn said. "I felt like, 'Okay, you know, my mom's still here. I still get to see her.'"

And mother and daughter agree on whose decision this whole gymnastics thing was:

"When I would come home and she'd be, like, 'Are you sure you want to do it? Are you sure you don't want to go try soccer?'" said Shawn. "I'd be, like, 'No. You know, I love it. I love the hard work. I just want you there to support me."

Parents Teri and Doug brought their only child to a gymnastics studio because they had trouble keeping up with her.

In 1998, Shawn and Teri met coach Chow, a former gymnast from China who came to Iowa to study English.

Chow told Rocca when he first met Shawn he didn't notice any spark: "No, did not think all that. Nobody can see that far. If somebody or any coach tells you, 'I see at six years old, she'll be Olympian,' that's not a truth. Nobody can see that far."