The big difference is limitations on sexual behavior: there pretty much are none that aren't up to personal choice. When you're a teenager, there are certain things you just take for granted, rules, dating etiquitte, etc.

Adults have a huge array of rules, and you'll have to learn how to determine what they are in each situation. Some women will not sleep with someone for at least three dates, no matter what. Some will be highly insulted that you didn't try to get into their pants immediately.

You're used to that one girl. Now, you're going out into a world full of different girls.

Good luck with that, M.