A training bra is a significant purchase for preteen and teenage girls. Many girls start developing breasts as early as eight years old. A training bra should be purchased when breasts begin to develop. However, some young girls start wearing a training bra before they need to to keep up with their peers, which doesn't do any harm and can help with self-confidence.
Remember to take your daughter for a proper bra fitting before purchasing a training bra to make sure there is ample support for developing breasts. It is important to start good bra wearing habits early. A good fit and style is important -- especially for a training bra.