I went through almost the same thing in highschool, we talked about marriage, but we had no idea what love really was. I am not going to tell you how to feel about your situation I will simply elaborate on mine and let you see how it turned out. Me and my gf in highscool were together almost constantly, we grew almost attached unable to imagine ever being apart. This is where the relationship began to change. What kept us together for so long was the feeling that we needed one another or that we couldnt be alone. Whatever love or emotions were involved early on had turned into need, I didnt treat her well, I was very jealous and controlling. I expected her to fill in for all of my insecurities and my world was very based on her. We stretched it out until 2 years after highschool when it came to a very ugly end. It all could have been avoided if we had simply seen the early signs and realized we were merely attached and not in love. Once again, not telling you what to do here, but high school relationships are rarely love, but it takes you looking back to see that.