My daughter is in the first grade. There are children in first grade that have boyfriends and girlfriends. These are normal baby crushes but don't add up to much.
Where I think it is getting out of line is when parents start to encourage actual dates.
Recently we had a school auction. One of the mothers won a trip for her kid and three friends to go see a live performance of Cats. She had her son invite the little girl that he likes. Then she invited two other first graders that liked each other so they could have a double date.
She purchased a corsage for her sons little boy, had him walk to the door to pick her up, open the car door, and take her to the door when it was done. She said this was to teach him how to treat women.
The next week the boy thought it was okay to kiss the girl on the playground. He kissed her on the lips.
I may be a prude but this is not okay for first grade. If they start this behavior in first grade what will be left for teen years?