Sounds like there is a lot of confusion between the two of you right now. In your post, you said you want to clear things up, and you want to start to do that the moment she arrives for the weekend. That's great.
Tell her everything you feel and ask her how she feels about everything. I would not put so much emphasis on the fact that she is your first relationship. I would focus on getting to know her, and letting her get to know you. Treat it like an adventure.
You sound nervous, but overall your attitude is wonderful. Relationships are an ongoing process. This weekend will not be the last time you will want to clear things up with someone. Focus on opening your heart to her. Give her the chance to open hers to you. See where that takes you.