Never seen any, i have a 13 year old girl, i have looked and purchased in both the uk and france for small bras.
Girls come in different shapes and sizes
Girls start to develop at different ages
A very rough and ready estimate can be given though... Here is an example from
brasizechart.info
Age 10: Training bra
Age 11: A
Age 12: A
Age 13: C – Says breasts grew quickly between ages 12 and 13, which is typical
Age 14: C
Age 15: C
Age 16: D
Age 17: DD
Age 18: DD
Age 10: First changes and training bra
Age 11: Training bra
Age 12: Fulll A
Age 13:Full B small C
Age 14:Full B small C
Age 15:Full B small C
Age 16:Full C
Age 17:Full C small D Depending on bra maker
Age 9: Training bra
Age 10: A
Age 11: A
Age 12: B
Age 13: B
Age 14: B
Age 15: C
Age 10: Training bra
Age 11: AA
Age 12: A cup bra
Age 13: A cup bra
Age 14: 34B sized bra
Age 10: Training bra or A cup
Age 11: A
Age 12: B
Age 13: C
Age 14: C
Age 15: D
Age 16: D
Age 10: Training
Age 11: A
Age 12: A
Age 13: B
Age 14: B
Age 15: B
Age 16: C
Age 17: C
Age 18: C
Age 19: C
Confused??? Me too.