Celeste ALREADY knew that she was staying there.
Celeste knew ALREADY that she was staying there.
Which is correct?
"I am already a millionaire"
But before you jump to any conclusion, take a look at this:
EN: even if I already am - WordReference Forums
2) you could put it before the main verb or at the end of the sentence, or even perhaps at the beginning of the sentence.
I have already seen the movie.
I have seen the movie already.
3) look for some question sentences as well.
I already earn more than I need.
I have already told you that.
I am already there.
I am already earning anough.
It can also go at the end of a clause for greater emphasis.
This explains why both of your original sentences are fine.
Auxiliary Verbs - Glossary Definition - UsingEnglish.com
Linking Verb - Glossary Definition - UsingEnglish.com
2- "BE" as full verb can be a linking verb in some cases:
"It is nice."
I wonder if "BE" is linking verb in the following sentence:
"There is a cat on the roof."
3- I already have a course book. (here "have" is a full verb, as you know)