As it isn't possible to reduce fat at 1 place only, i suggest to lower your total body fat percentage...
The most important thing to do, is to control your diet so you burn more kcals then you eat. The best amount is about 500 kcals below that... But if it isn't simple to control your diet like that (your parents dont agree with it, you dont have a lot of time, whatever other reason) you just have to do a lot of cardio to make sure that you eat less kcals then you burn!
Also: Just keep lifting heavy weight. Try to train your chest muscle well, it will sort of lift your breasts. Normally, if you do enough cardio, you won't gain too much muscle mass.
And even if you do... I know guys that train for 20+ years and aren't even near Ronny Coleman, not like you will become a female version of him in 1 day
