Why do we need to use the definite article "the" in front of the adjective "first" if the meaning of this sentence is complete without it right there?
-When I met her for the first time I couldn´t help but fall in love with her.
Why do we need to use the definite article "the" in front of the adjective "first" if the meaning of this sentence is complete without it right there?
-When I met her for the first time I couldn´t help but fall in love with her.
Generally, if you a restrictive relative clause is implicit, the definite article is needed.
When I met her for a time which was the first
When I met her for the first time ...
In some sense you are correct, but only colloquially (e.g. first thing in the morning). The simple answer is that "for the first time" is an idiomatic. This is generally true for superlatives (the biggest ...) and similar to French (grand, plus grand, le plus grand ...). Omission of the preposition "for" is also common in American English.