I'd say for you to keep studying grammar (and from grammar books) and I am going to tell you why. 

I never studied English grammar. What I learned so far is through assimilation. I didn't have teacher, I didn't attend to a course and today I know how important grammar is. I used to think I could learn English without studying grammar - actually I know it's possible but at certain level grammar is needed. Today I know grammar isn't a stone in the shoe: it's the shortcut! Of course, many language courses today are filled with grammar and grammar (Aaaah!) and it doesn't mean preparation. So keep studying the essential grammar but the most important is to practice. Don't forget that you also learn grammar unconsciously by practicing. 

For example: you can learn how to play a song in an instrument by memorizing what to do but you can't learn how to play the same instrument if you don't study the musical notes (please, if there's any musician, correct me if I'm mistaken). 

Anyway, I'm far from "mastering" English but I know that if I want to reach another level then I can't hide myself from our good friend called grammar... anymore. 

Marco, if you are worried about doing a language exchange because of your level (which there is no need to be worried, but I understand) then I highly suggest hiring a community tutor here at Italki who is a native English speaker. They will help you to practice using in a real life situation what you are learning from your books. I know so many people that have spent even DECADES learning from books but can't SPEAK! 

Get on Skype and say those words that you are learning in your books to another person and they will come to life for you and start to make sense and stay in your mind more easily. When you HIRE SOMEONE to help you, then all your fears about "being ready" or not to speak should go away because you are paying them to be patient and help you. 

If you hire an accredited teacher here at Italki then they practice that grammar with you in English. They will help you to say and use what you are learning and that can be also very powerful. 

After even just a little talking with a real person I guarantee you will be hooked. It's the most wonderful thing in the world to bring those books to life and have a real conversation in another language. 

It's time to talk Marco! :D

Thanks to everybody!

You gave me the bravery

I will do it :)

Of course you are ready, Marco. Nobody is expecting you to be fluent or for your grammar to be perfect. There are a lot of native English speakers here who would like to practise their Italian, so why don't you look for a 50/50 language exchange?

I think what is stalling you is the fact you are learning in a vacuum.  The best thing for you, especially now, is to find people to speak to! This way, you get practice and feedback.

There are plenty of English speakers around (and I think we're pretty tolerant!), so native or non-native, you can find conversation partners easily. :)