I wonder how could you not to fail when it was your first date. Be softer to yourself, you did well.
Think its important next time don't take her too seriously. See her more like a friend. Mistake before was that you fell under beautiful women spell. When this happens look for things in her thats not perfect, look critically at all her imperfections. If you put her on the pedestal then you cant reach her anymore. Only way how to reach her is bring her down or put yourself up.
Also I can tell already that you think too much about her. This will make you only more awkward in person. Try to be busy so you have to think less of her.
Doubt kills more dreams than failure ever will