When referring to a time that is earlier than it should be, there are a multitude of synonyms you can use instead of "too early." You could say something is "premature," "untimely," "precocious," "unseasonable," or "ahead of schedule." If you want to indicate that something is happening before it should, you might use "premature," "trustless," "hasty," or "impatient." Alternatively, you could indicate that something is happening earlier than normal but not necessarily incorrectly by using words like "early," "previously," or "beforehand." No matter which word you choose, the important thing is to convey to the reader or listener that something is happening too soon or earlier than it should be.