Is 54 pages per book good for writing a novel divided into 3 books? Which means every book has 54 pages?

Counting in terms of pages is generally the mark of someone who does not know anything about writing. If you ever try to get professionally published, at least in the US, and you talk about pages, you’ll immediately be branded as a complete beginner, and decrease the chances anyone will want to work with you.

Pages are different sizes. Fonts are different sizes. Margins are different sizes. Saying a story is 54 pages doesn’t tell you anything.

Words. Always words, never pages. How many words is it?

I’m guessing not many. 54 pages sounds like a short story, not a book.

The average size of a published novel is 94,000–96,000 words. Some genre fiction (mainly romance) is a bit shorter. Science fiction and fantasy is usually longer, typically 120,000 words or more.

In the US, most publishers tell you in their submission guidelines that they will not accept anything less than 80,000 words.

I’m guessing your 54 pages is probably about 10,000–12,000 words, which is definitely not a book, it’s a short story. You need 8 or 9 times that length to be a book.