Bat & Glove Sizing

Glove Size
For softball players, 6 years and under, a glove size between 9 and 10 inches may do for all positions; a glove size between 10 and 11.5 is ideal for ages 7 to 9, also for all positions. For players ages 10 to 14, infielders may fit with 11.5 to 12.5, while outfielders can opt for 12 to 13.
Bat Size
The key to finding a good Fastpitch bat is getting the perfect size and weight that fits the player. Fastpitch softball bats range from 26 - 34" inches long. Fastpitch softball bats have a drop weight ranging from -8 to -13. The drop weight indicates the length to weight ratio. This is typically shown on the bat. (FYI, Bat weight affects the swing speed.) 
For girls playing 8U and 10U level then the focus should be more on the correct length since the lighter bats are more expensive and the girls quickly out grow them.  For experienced players in 12U and above you would choose the correct length from below with weight ranging from -10 to -13.  But keep in mind that these bats can be expensive.