Funny love

You are a teenager around 15-19 years old. Almost every day you are hangin' with your friends on stairs in front of the building. From time to time you see mother with a little daughter passing by. You have no feelings for little girl that was passing by. Although you find her mother rather attractive to you.
15 years later you are walking through life with a little girl that was passing by with her mother 15 years ago. You love her very much. You even think you couldn't stand living without her.
Where was that so called love before, when she was a little girl or when she wasn't around. How could it just evolve from nothing. Was it created by need for reproduction?
That isn't true love for me. True love should be omnipresent all the time without any conditions. Unconditional love, that is the true love.
Are human even capable of loving just one person? I think that true unconditional love have such energy if concentrated on one person it can incinerate that person. Being burned by love. Is it even safe to love just one person?
Is today's meaning of word love just another name for need of your expansion with children, because you have felt the fleetingness of your life, and you want to leave a mark on Earth in shape of your children. Are people of present day even capable of unconditional love?
Will you be able to love her in 15 years with the same ardor in which you love her now?
I'd like to have your opinion on this!