“Too Early” is correct because “too” is the word which means “more than enough”.
When you say that you are “too early”, that means that something happens a lot of time before the correct time.
8am is too early to start school. It should start at 9am.
Can we meet on Sunday morning at 9am? Is that too early for you?
We often use “too early” in the context of early mornings because some people do not like waking up early.
Too vs To
To is a preposition and part of the infinitive of a verb.
I am driving to the cinema.
I need to drink water right now.
Too is an adverb that means “also” and “excessively”.
I miss you too.
I ate too much chocolate.