Can I still bless the moon on the night that is 14th of the month? I also want to know ,please, if it’s necessary to do it after Maariv or can you bless it before.

The Shulchan Aruch and Ramah (Orach Chayim 426:3) wrote that blessing the moon is permissable until the night preceeding the 15th of the month (including that night). There is a rule that states: "Often and not often - often has priority" hence, regularly Ma'ariv should be davend before blessing the moon; if, however, there is some concern that the moon will disappear, such as on a cloudy night, the moon should be blessed first. Rabbi Ro'i Margalit