No, it's not strange. My girlfriend has broad shoulders - she could be on a hockey team - but she's still gorgeous, and my friends have commented on how hot she is, as well as how broad her shoulders are.
Not strange at all. People have all kinds of bodies. Girls can be big and strong too. Exercising, playing sports, or just moving around a lot gets you that kind of body. And it can look great, feel great, and be healthy.