Many women have problems with the proper bra size. Often it is simply too small or has a too wide band, and therefore does not provide adequate support for women's breasts, which significantly reduces the comfort. Therefore, if you do not have a matching bra, this first one is really worth buying.
On the web you will find plenty of advice on brafitting and how to find the suitable bra for yourself. You just have to measure yourself under the bust and in the bust and then check the dimensions in the provided chart to find out your size. You can also go to a good lingerie store where you will get a full service - brafitter will measure you and then propose several different bra models. Also she can show you how to properly wear a bra.
Then you will easily be able to wear a strapless bra - that is a big challenge even for larger busts. You'll find also that a proper bra will change your figure – it will be more slender and you'll certainly end up pleasing herself in the mirror. Therefore, a fitting bra is a very good investment!