Hiya - well, first off, you posted at what was, to me, about 230 AM. And it was the middle of the night for lots of people. Hence the lack of responses.
Now - you have had a long-distance relationship for going on two years. It makes perfect sense to not be talking marriage during it, particularly given your age (I assume she is close in age to you). 17 is awfully young to be thinking about forever commitments. Your life expectancy is something like 50 - 55 more years. That's a really long time.
Forget the anniversaries and the special days, yadda yadda yadda. Just go there. Knock on her door (bring flowers if you like, but that's not necessary). And say, "I love you. I'm moving back here."
And see what happens. Frankly, if it was me I'd be kinda surprised but probably, ultimately, glad.
But you need to also understand something. During this time period, you have been in an extremely safe situation. You maintain chastity because of the distance and your ages. You don't truly commit because of the distance and your ages.
And you also don't open yourselves up to seeing other people, or taking risks. It is extremely safe. And that does not mean that it is not right but understand that most people take at least a few small risks because that is a part of changing and growing. It is a part of becoming a mature adult. You see the world (or at least as much as you want to, and can afford). I'm not saying that you use people or break hearts, but you do try on relationships for size. Some are better than others.
Your being back is going to change things, big time!
You are also both older. The temptation will be there, and you won't be able to shrug it off as distance if you are in a situation where you can have sex. I am not saying that you will, but when you're a thousand miles away, all of that is conveniently and neatly (and safely) decided for you. When you're a thousand millimeters away, it's not so easy.
You will also, I suspect, find a lot of the honeymoon type phase going away, as you will undoubtedly see each other more, and sometimes that will not be when you are both at your best. It is one thing to only text, chat online or call on the phone when you are perky and happy. But you may find you have made a date but you're tired from work. And you don't want to break the date, so you go anyway. And tired people often pick fights. Fighting is fine, and it's natural. Long-distance deals either are loaded with fights or have close to none, and neither are healthy.
I've rambled enough. But things are going to change.
Remember - this is not a marriage proposal. This is just you saying you are moving back. Period, end of story.