Before booking a honeymoon I would always want to talk through options/ideas, what does the couple want from their honeymoon (activities, relaxation etc) and what is the couples objective.
It is never too early to plan your honeymoon. Couples often think that leaving the honeymoon planning till the very end will mean they get the best offers and discounts. This is actually not the case and the best offers are available when planning in advance and many couples are able to take advantage of this.