Trying to determine this decision with a girl I am seeing. I am in my later 20's, and she is 22. I know she is looking for a guy to date seriously, and we have hooked up. In the past I have played by the rule of 3-4 "real" dates, which I usually consider to be going out to dinner and spending an evening together, versus a quick coffee or something like that.
Obviously it depends on how things are moving on the dates, but she has been instigating most of the communication and stayed over after the last date. I haven't had a problem in the past with having the conversation after the third or fourth date, but I know everyone is different.