Only as important as you say it is. You don't need one, but they can make your life better or worse, depending on who it is. A lot of girls (young ones, below age 20) have boyfriends mostly as social status symbols so they can say "I go out with so and so," since long-term partnerships are rarely formed at these ages. If that is why someone has a boyfriend or girlfriend, then it is not that important. If you come across someone who makes you feel loved and treats you well, then it becomes important to move closer to them.