First bras are amazing milestones, but they can be intimidating. Here's a quick guide on what to look for and how to shop!
Go to your local bra shop. The professionals there love to help, and can guide you through the process. Look, it can be scary to do such personal shopping with a stranger, but bra fitters have seen it all. All bodies are beautiful and fitters are here to help you.
Wear a tank top or thin layer, you'll keep that on for the initial measurement. First, you or your fitter will measure around your ribs right under your bust, keeping the tape level and snug but not too tight. This number is your band size. Bands come in even numbers- 30, 32, 34, etc. Round up to your nearest even number.
Your cup size is based on the difference between your band measurement and the measurement around the fullest part of your bust. Generally, each inch is a letter. The shape of the bra might influence the size of the cup.
There is no such thing as a "D" or any letter for that matter. The cup size is relative to the band size. The letter doesn't exist without the number. a 30D is a much smaller D than a 40D. What matters more than the size is the fit. Don't worry about the number and letter on the tag, focus on the fit. You might be different sizes in different brands or bras!
The band should be snug but comfortable. If you're still growing, buy a bra that feels good on the tightest hooks. As you grow, you can let it out. Once you stop growing, buy bras that are snug on the loosest hooks so you can tighten the band as the bra stretches and wears. Out of hooks? Time for a new bra!
How do you know if the cup fits? You want all your breast tissue in the bra. The underwires should be all the way back behind your tissue. Your breast tissue shouldn't spill out anywhere, nor should you have space or wrinkles in the cups. Everything should generally lie flat on your body and not move.
Take your time and try on many different styles, sizes, and construction. Bras are an important part of our daily wardrobe- take time to find something that makes you feel amazing! Fit, fabric, color, it all matters, so have fun!