i am 16 years old. i wear a size 34D but really don't look it, my boobs look smaller. but in between my boobs (the cleavage or skin tissue above the sternum) is squishy instead of hard. for most girls you can feel their sternum in between their boobs, but for me its squishy and you have to push down on the skin to feel it. why is that? is it just a part of my boobs growing? will it gett flatter over time?