I don't think God created time. Just ask yourself, "when did God create time?" What was He doing before then? Time is not a created thing but rather a description of events as they relate to one another. Time doesn't answer where but when. As it relates to God, time is endless duration, because God has existed eternally. Was there ever a time that God did not exist? No. The Trinity has always existed and for communication to happen time must exist for the conveyance of thoughts. I propose that time exists because God exists.