If you think a particular girl is funny, and she thinks you are funny, that's a great sign! My elementary school was a lot less puritanical than my sons' not that there was much more than talk, but we weren't all that naive.
Datiing it was gross kids should not do that that young.
This can be seen at the local level, where adjacent districts can differ on what level sixth grade occupies.
However, at age 18 is when I would feel that dating is appropriate 6th grader dating acceptable.
They are far too immature to begin to handle feelings of sexuality in sixth grade.
For the past twelve months I have routinely found myself having to explain to potential students why they can no longer add Archaeology to their studies and I have seen them pull the same face I did at their age when I was offered the alternatives.