It’s totally normal to have boobs that aren’t the same shape and size, especially while you’re still growing and developing.
Here’s why: Boobs grow because hormones - the natural chemicals that control puberty - circulate through the body, instructing various parts to stretch and change. Even though hormones float all through your body, the body parts don’t always respond to them at exactly the same time or in precisely the same way. This is why it’s really common for girls to have one breast bud weeks, or even months, before the other one ever appears.
As you continue to grow, your boobs may even out a bit - or they may not! Both are completely normal and nothing to worry about.