There are certain things that are not to be shared on a first date. If it has to do with sex, drugs, or any other illicit activity, then hold off… maybe forever. Lots of things fall under the sex category, including nudity, number of partners, pornography, strippers and so on. Anything along those lines should be considered over-sharing. Drugs include both the prescription kind as well as the illegal kind. No one needs to know about that on a first date! Money, why past relationships ended, and anything having to do with drama can wait for another date.
First date topics should start with continuing the email conversations you began, which usually address your commonalities. Just let it flow naturally from there. If you find the rapport waning, then revert to asking questions from the JDate profile. “Remind me again where you went to school/where you grew up/what you do for a living/how many siblings you have?” Those are always easy ways to get the conversation going again.