Phennie'sBig Girls Training Bras Slim Soft Cup Hasp Teen Small Vest Design Wireless Bra

Will these fit a teenage girl? She is lean size! 34 seemsmore of a woman.

i’m a 30-32D cup but fit into a 32-34C. Should I buy these?

I am a very petite 35 year old. Do these have any padding or any kind of a push up effect?

Are these stretchy? My bust size (34 inch) puts me at size 36, but my band size is 31 inches. Is it better to size to my bust size or my band size?