You are severely misinformed. Jehova is not our G-d. Jehova is a bastardization of G-d's true name, often called "The Name of 72 letters."
Jews believe that there's power in the Names of G-d, and that they should not be spoken lightly (in vain, if you will) nor printed where they may be erased (Thou shalt not defame nor destroy the name of thine G-d.)
Technically, Christians worship our G-d too, as the Father part of the Holy Trinity.