Selena Gomez thinks she heard things she wasn't "old enough" for as a child.

The 23-year-old singer-and-actress has been in the business since she was just a kid, landing a role in TV show Barney & Friends in 2002.

It was her first taste of fame and meant that the star grew up much faster than many others.

"I was seven when I got my first role," she recalled to German magazine TV Movie.

"Even though it was a kids' show, I was surrounded by adults all day. I listened to them a lot and started to talk about things I probably wasn't old enough for [laughs]."

Being a celebrity comes with its stresses, with Selena spending two weeks in rehab at the beginning of last year. It's unknown why she decided to check herself in, just that it wasn't because of drugs. Some claim it was her on/off relationship with Justin Bieber that caused her to need some time out.

But there are upsides to fame too, and Selena feels particularly proud when she can do things many others her age aren't able to.

"When I pay my mortgage," she exclaimed when asked when she feels most grown up. "It's the most expensive thing I've ever treated myself too, but also the best."

However, Selena also indulges her more childish side when she's with her family in Texas.

"I don't have any responsibilities there and can just be myself," she smiled.