Don't create an imaginary scenario, or dwell on what it will be like beforehand. Reality doesn't work like that. You won't enjoy yourself if you go in with a 'list' of things to do, for trivial things like positions for sex etc. Save that thinking for specific scenarios like dom/sub sessions with someone you've met before.
If you are hesitant because of the amount you're about to spend, then don't spend it.
If you're seeing someone for the first time, go in with zero expectations. Assume it'll be an average, perhaps even a bad time.
As for the meeting itself, the best advice I can give is that I always try and avoid the girl's "ten commandments" by first asking her "what don't
you like doing?" as that feels like more of an ice-breaker and puts her a little at ease, in that she doesn't feel so mechanical reciting her list, and is aware that I know she might not do certain things, etc.