Am I doing the PostgreSQL database structure correctly?

Question

PostgreSQL

I decided to make a website, I started with the database structure. In two days, I have already accumulated 18 tables, this is according to the rules of data structuring, one-to-one, one-to-many relationships. I think there will be about 25 tables in total.
To load one page of the site, you will need data from all these tables and the sql query (with sub queries) will probably be 50-100 lines long.
This is fine?
How fast will PostgreSql think over a single query if relationships and indexes are set up correctly?
Thanks in advance for your replies and comments.

Answer 1

if you need to select from all tables to display the page, then you have a problem with the architecture.