Yes, possible, but in the the circumstances you usually see. Like couples who've been dating for 2 months and only knew each other a month before that... A good case would be two people who had spent their childhood together and probably both had rough problems or something else that could've made them really close((like they were both abused and so they were always the first one to be there for each other, which made them really close)). But that itself could end up as a sibling love instead of a romantic love. So the odds of a romantic love spawning from something like that is even rarer. Usually, what all the little school-kiddies run around calling love is nothing but a discovery of lust.
What you said there has made my mind twist and turn. Then what I have with my GF is just kid's play?