Why are my boobies so small?

i was a Very chubby kid in the 6th grade nd my boobs were fatty. i had my period in the 7th grade my boobs didnt grow much now i'm in the 11th grade i think my boobs are the exact size like they were in 7th grade. i wear a size 34 b bra size with padding. is there anything i could do to make them bigger?