06/15/2012 02:40 pm ET

Jamie Lynn Spears Sings Song About Britney Spears (VIDEO)

After giving birth to her daughter, Maddie, at the age of 17, Jamie Lynn Spears stepped out of the spotlight, leaving behind a starring role on a hit Nickelodeon show.

Now, the 21-year-old is trying her hand at show business once again -- this time as a country singer. On Thursday night, Jamie Lynn took the stage at 3rd and Lindsley Bar and Grill in Nashville, Tenn, where she performed a song about her older sister, Britney.

"This next song is called "I Look Up to You." You can imagine who I wrote it about. I hope y'all like it a lot," she told the audience before singing the ballad.

In the song, Jamie makes reference to how Hollywood hurt her sister and stole her "innocence," and sings, "Scared little girl living in a big old world. You've outgrown your room, it all happened way too soon. They took away your innocence. We forgot our strong defense."

Both Britney and Jamie Lynn were forced to grow up quickly in their own ways. Britney's career solidified her as a sex symbol by the time she was 17, and Jamie Lynn said goodbye to childhood when she became a teenage mother in 2008. The former "Zoey 101" star recently spoke to Glamour about her life as a teenage, and now single, mom.

"I was 16. I'd had one boyfriend. It doesn't make it perfect or all right. But I was judged for something that probably most everyone does. I was young. I was in love. I was like every other teenager, except I had this last name," she told the magazine in February.

That last name, of course, is one shared by her older sister, who was dealing with some serious issues of her own at the time of Jamie Lynn's pregnancy.

"I wasn't trying to glamorize teen pregnancy," she said of her decision to talk to OK! magazine about her situation at the time. "I hated when [the tabloids] said that. Everybody is dealt a hand of cards. It was my choice to play them the way I played them."