We've truly seen JoJo grow up in front of our eyes. Just 13 years old when she broke out with "Leave (Get Out)," this big-voiced singer turned 21 in December. (We know, it makes us feel old too.) Right now, JoJo is reaching out to teens to help promote safe driving though AT&T's It Can Wait pledge against texting while driving. Keep clicking as she tweets with Wonderwall about her own texting habits, her new song, "Disaster," and more. When you're done, make sure you're following @WonderwallMSN and @JoJoistheway on Twitter. Then, click here to take the It Can Wait pledge.