LOS ANGELES (CBSLA.com) — A Southern California family spoke publicly for the first time Wednesday about their child transitioning from a boy to a girl.

“I felt like I was an actor in a TV show playing a character except it was 24/7 and there was no escape,” Lily Rubenstein, who was born a boy, told CBS2’s Kristine Lazar.

“I’ll never forget it. She was shaking uncontrollably and just said, ‘Mom, you need to come sit down on the couch with me. I have something to tell you,’ ” Britt Rubenstein, her mother, said.

Lily came out to her family as transgender when she was 12.

“She said, ‘I feel like a girl inside and I want to start dressing like a girl and this is who I am,’ ” Rubenstein said.

Lily’s parents were blindsided because they say their daughter had never showed signs that she wasn’t happy being a boy.

But right around puberty something changed in their once easy-going child who was depressed and struggling at school.

“We started to see this steady decline in our child,” Rubenstein said.

Lily, with the support of her family, decided to make the transition to a girl.

“It’s not really a decision to transition. It’s necessary. I could no longer go on as my former self,” she said.

Lily has been receiving hormone therapy and blockers to stop puberty at Children’s Hospital Los Angeles, which is home to the largest clinic for transgender youth in the nation.

“The trans-experience has been happening since the human experience started,” said Johanna Olson, an adolescent medicine physician.

Olson treats more than 400 trans-youth, the youngest of which is 4.

“Kids do roll through a lot of things as they go through identity formation but our gender is a core part of who we are and we actually all know what our gender is and have pretty solid gender identity by the age of 3 or 4 years old,” Olson said.

Lily just this year told her classmates at her new school, where she has only been known as a girl, that she is transgender. She read a poem aloud in class.

“I wrote about the good times. I wrote about the bad times or about the stressful times. I wrote about the really awesome times. And I wrote in there about friends that have left me because of this,” she said.

The high school freshman has never spoken publicly before but her hope is that, in doing so, she can inspire other transgender youth.

“Looking back on when I wasn’t happy, I was always thinking about the present. And now that I’m happy, I’m always thinking about the future and I think it’s a great thing to be able to do that,” she said.

The Rubenstein family gave their neighbors a letter telling them their daughter was transgender and say they’ve received nothing but kindness.