Your first idea is a natural way to think and behave. If you wonder why or what is happening go ask, totally authentic.
Your second idea of trying to determine whether what you say will weird the girl out is something I would advise against. Firstly, this will take you out of the moment and into your head. Secondly, and more importantly, don't second guess yourself, trust yourself, and don't speculate about how people will recieve you, it is unknowable. If you must assume anything, assume you will be recieved well.
Everything that advances can be said to do so by a process of performance, feedback, revision.
Performance. Say anything.
Feedback. The other will respond.
Revision. Your mind will naturally and automatically assimilate this response into its overall theory of social interaction.
... round and round and round. Each revision being an improvement on the last.
Performance, feedback, revision.
http://m.youtube.com/watch?v=hod20AzYB4 ... =mv-google
Peace,
kowalski