How long after you start dating someone should sex occour?

For many younger people, like high schooler, sex is as common as using the toilet-nothing special, so they have sex on the first date…

For older adults, they wait a bit till they get to know the person…

Waiting until marriage runs the risk of marrying a person who is sexually incompatible, so you shoud know you are compatable before making a lifetime commitment…

For most adults these days- How long does it usually take until sex occours? After a few days of dating? A few weeks? A month?

My experience has been about 3 weeks..

Answer
3 dates! That is the unwritten rule.