I dont see the point. You think that you havr finally found "the one" each time you fall in love. But you cant know that you will marry that person, so then you are wrong, making the whole thing a waste of time.
No, it's not, if you are mature enough to appreciate it and nurture it. Most very young people don't have the wisdom or stamina to maintain long term love relationships. Trust me, love is not enough. You have to love each other, bring commitment AND a willingness to compromise cheerfully when circumstances demand, to make work. If you really love each other though, it won't seem like much "work" at all.