Diane

I think they’re beetween 16-18. It could be that they aren’t all in the same class. Because in "Last day of school" Sci-Twi and RD are in the same class, so they’re the same age and juniors. Also in "FOMO" we see Rainbow Dash driving a motorcycle, so she's 16-17. Sci-Twi doesn’t drive a car, either, because in "Friendship Games" and "Monday Blues" she takes the bus. So she’s the same age as Rainbow. Fluttershy is older, I think. In "Driving Miss Shimmer" she has her own car, so she’s obliviously 18. Sunset Shimmer, too. Also Rarity and AJ. About Pinkie Pie, I really don’t know. I think she's 17, because we all know Fluttershy is a year older than her. Also I haven't seen her drive a car or something.

I like her ^^ I think, behind that "cool" and confident side of Rainbow is also a cute and friendly side. In the most moments she's brave and said, she has no fear, but I think, even SHE has some inner fears. Rainbow is my fav pony, I love her appearances in the show and she's voiced by my fav voice actor Ashleigh Ball <3