Yes, it is entirely possible for a girl (or anyone) to live their whole life without getting married or being in a long-term romantic relationship. Living a single life is a valid choice that many people make for various reasons. Some individuals may prefer independence, focus on their careers, have other fulfilling relationships, or simply not feel the need for a romantic partner.
People can find fulfillment and happiness in many different ways, and being in a romantic relationship is just one of the many possibilities. There are plenty of single individuals who lead happy, successful, and satisfying lives surrounded by friends, family, and pursuing their passions and interests.
It's essential to respect each person's individual choices and preferences when it comes to relationships and not assume that everyone desires or needs to be in a romantic partnership. The most important thing is to lead a life that aligns with one's values, goals, and desires, regardless of societal expectations or norms.