Astrology has power because it offers interpretations that fit you and some that will be true (they are not necessarily the same)
Green and Red: (I wonder if our signs are compatible)
The reason why astrology prospers.
As he thought there must be something between them, Red decided to see if astrology could confirm his impressions. He realized then that he did not know the date of her birthday. Green faced the same problem when she wondered if fate could have made them meet. So they both sought out which signs were compatible with theirs in case they got the missing information, and then dropped it.
Astrology, anyway, was not a real science, was it? Why bother? Nothing it could have said would have changed the fact that on the ground the situation was still rather indecisive. They had to decide if the story was a story to follow, they had to live without knowing if they were making a mistake. At best, the signs could have indicated a direction and some hope, but they were silent and that was perhaps the best answer they could give at this point.
Of course, that both thought the same thing at the same time would have been a good indication of their connection, but that they did not know.