Fitbit to Release Fitness Tracker for Kids The Fitbit Ace is designed for kids ages eight to 13 and carries the same functionality as the fitness tracking brand's other products. The Ace counts steps, helps track sleeping patterns, sets move reminders and other features. Parents can even add their children's ace to a family account to track their progress. With the Fittbit app, kids can add their friends and compete with fitness goals, as well, according to TechCrunch. Pre-orders for the Ace start today at $99.