You were offering something to the members of the forum. You were not simply looking to exchange information. You literally said you were going to read the energy of the months and create a calendar for people to use to plan out their rituals based on your reading. That is the offering of a service, and is prohibited until you have been an active member for 90 days.
This is no different than if someone offered to draw tarot cards and is covered by the 90 day rule.