20 Years Old, Puffy Nipples: Are my breasts tubular? (photo)

Judging by your photos alone, your breasts do not appear tubular. They are just youthful. By 20 years old, your breasts probably won't grow anymore unless you gain a lot of weight or become pregnant. 

Based on the photo it doesn' look like they are tuberous an in person consultation with plastic surgeon is recommended.The tubular breast
deformity is surprisingly common and consists of a large nipple and areola
complex herniating outside a small and constricted breast. This deformity
is often corrected with breast augmentation and various forms of periareolar
surgical techniques

Maybe a very very minor tuberous component. But yes to be seen IN PERSON by a boarded PSs in your city.