Help me for my first date?

Hi, theres a girl. Uptill now i call her a friend but actually she is like my gf.

So, b4 1 year i was unable to propose her and tell that i luv her. We were friends from last 4 years. There was some situations, so i did nt propose her. The other guy proposed her, and nw she is in relationship with him.

Bt i and she think that he is cheating her. Bt then also she luvs him bcoz she is so emotional gal that she cannot break up with him.

Now, i've told her everything. Nothing is untold, unsaid. She also respect my feelings for her. And she is giving me chance to know her well and she also wants to know me. I truely love her from bottom of my heart. Tomorrow we are going on a long ride on bike. We don't know where to go. But my problem is i get nerves in front of her. I don't know why is it my true love problem or what. I just get lost. I chat with her whole day and night. I talk ok on chat. But when i meet her something happens. I just cannot show her real me. And i don't get topics to talk about. We are so close that we talk about marriage also. We are serious with each other. She is giving me a big chance.

So please help me what to talk tomorrow and how to be real me. What to do. Oh god, please help me. Hope i won't make her bore. Guys wish luck for me. Its my first real date in my life with my true love. And i am one woman man... I'll end with her only. She is understanding gal. She knows everythink in my heart. And i am platonic lover of her. She lives 10 kms away, but somehow i get to know she is sad or happy, she is crying. It might seem funny for you. But its reality.

So help me for tomorrow. What to talk about and be in the flow. I am not a natural flirt. I cannot act...