Girl you are lucky, lucky, lucky!
First of all, you will NEVER look like the pics you show above. Never– and count yourself blessed. It means you’ll look like a woman and not a boy with tits. Your basic shape is genetically determined, so you have your mother, father, and all their forebears to thank for your luck.
With a pear shape and small breasts, you will have the lowest risk for breast, cervical, ovarian and other female cancers, as well as radically lower incidence of arteriosclerosis and heart disease. No kidding.
I know you’re keen to look like all of the thin teeny-boppers running about that look like sticks. Forget about it. As one man once told me, embracing a chick like that is like hugging a coat rack. Not a pleasant experience….Men like zaftig women, a woman who looks like she could kick some ass, run a race, trek through a stream and bear children. That’s YOU m’dear.
About those breasts: I had teeny ones too, a nearly-A all my life. Now I’m older (45) and into an A cup (woooooow), I realize that I look better than most of my peers: those babies haven’t fallen, and they look good in today’s fashions which aren’t geared toward the hugely endowed woman. It’s *breast tissue* my dear, not the be-all, end-all of existence. The man who loves you eventually will love you FOR your smaller breasts and ample hips. Did you know the French, who know a thing or two about fashion, think the perfect breast size is one that fits inside a champagne class? not a flute, but an old-fashioned flat champagne glass. By those standards, mine are too large !
What you can do to keep from putting too much weight on the ass, is LOW CARB living. See the works of nutritionist Jonny Bowden– all his work is GREAT for this, and he can explain the science behind it in all his books, most notably ‘Living the Lo-Carb Life,’ which has become a classic. Stay away from sugar in all its forms and you’ll be healthy, you’ll look good, and your blood lipid profile will be tremendous (High HDL, low LDL, and low triglycerides, most importantly).
ENJOY GIRL!! you’re one of the lucky ones.
I should know! I look Just Like You !!!

first, accept your body size.
second do cardio and limits your cabs. be do chest strengthening exercises like push ups and there is nothing wrong with push up bras..