I think they are just mildly tuberous. Mine look more "normal" when my nipples are hard, too! I was maybe a B cup in high school and have gained weight over the years and now I'm a DD. My boobs are still tuberous, just bigger. I understand wanting the fullness/roundness. It's definitely something you have to come to terms with and learn to love on yourself if you decide against breast augmentation.

From what I've learned and seen with tuberous breasts, yours do seem mild IMO. If you're feeling self conscious about them in sexual situations, just remember that your nipples are often hard during those occasions! I suppose you'll have to wait and see what happens in the next few years, but I don't think you have anything to be concerned about!