Will i got to hell? or should i prepare?

Ok, I'm not sure if its your young age (19 is a very critical age) but even in your question you have many contradictions. Take a true moment and reflect on what you just asked. You know the answer. Trust me, I do not preach nor accept anything other than ADVICE, there is no true word, wrong or right. That urge to tell her you cheated, that's your conscience (YOUR right / wrong meter). If you haven't seen your "girlfriend" in over 6 months, at 19 cut your losses, not for you but for her. Its prob hard to let a Model go but you need a solid on hand relationship to keep you in check. These are the years that will define your future lasting relationship.