My Boyfriend wants to marry me, I think he is the right one.. How do you know?

I have been in a relationship for 3years now. I am 17 my boyfriend is 18. we waited a year before we actually started dating, and will be waiting about 2 more years before we want to get married. He is my best friend, he is absolutely amazing and incredible just in who he is alone. I cant imagine how life would be without him. I have my promise ring and he hasn't broken his promise for 3years now. I can be my self when i am around him and speak my mind or cry if i need to. I think i am in a healthy relationship, although people make it seem other wise? Does it sound like its the right guy? Im not some dingy teenager who has my head in the clouds. I have standards and my head straight. I mean im 17 and im in college, i have to have my head straight as well as my life. I just wanted get other opinions :)