Nervousness just means that the outcome is both important and uncertain. It is not a statement about you necessarily, but that you are perhaps over thinking it and letting it build up as a disaster in your head. You don't know how it is going to turn out, so any crash type scenarios you've got playing in your head (I'm assuming that is what you are doing - that's what I do) are fictional until proven otherwise.
Letters, love songs, Scrabble, smoke signals, communicate however you think will be best for you to convey your feelings to her in a way that she can consume. Honesty is going to be best, focus on yourself and not her, don't be afraid to express your fears and desires.