Belly dancing is not only about movement of the belly or just dancing! It is an amazing exercise too that tone up your entire body and energize your mind too. It is very good for those who fight obesity too. There are many people who started practicing Arabic belly-dance moves from videos like this and have lost weight plus they picked up some great belly dancing moves. So, it is highly recommended for any body who wants to lose weight, or learn belly-dancing for professional reasons or to just have fun.
Shoulders may tend to hurt for some beginners if they overdo. Listen to the instruction and you can do it right. For practicing the upper body movements, it doesn't matter how big your breast size is to do shoulder shimmy, or other moves. The vibrating movement of the breasts is natural during a shoulder shimmy, and you can perfect it like any trained professional belly dancer does.
Many new practitioners report that belly dancing is really not too different from your basic dance warm-up with all the isolations. It is easier and better to practice the moves with your friends rather than doing it alone, especially if the moves are found difficult or if you cannot reach perfection.