Relative ages of Olympic Gods?

Well, one myth says that Artemis and Apollo were twins, born on the Island of Delos in a Lake there. I was there (Delos Greece) last fall and there was an old dry (drained in modern times because of a malaria problem) lake and temple ruins to both Artemis and Apollo. Artemis may have been the first out I guess? But they were twins so no real age difference.