It is worth to spend money and time for a drama school ?

First you can't just move to the US. You need to comply with all the immigration and visa requirements which can be daunting (https://www.dhs.gov/how-do-i/move-united-states ). The process doesn't change because you're a "nice guy". Because someone else did itdoesn't mean it will happen for you.

If you are able it immigrate and move to LA, you can just take acting classes. There are currently 100,000 professional, union actors just in LA and a few hundred thousand more wannabe actors, so there are a lot of lot-of-work actors having classes. Of course for a professional career where you study and who you study with matters. You don't need an acting degree (BFA or MFA) but quality acting classes from respected instructors are important, not just to improve your acting skills but to network and make industry connections.

And professional acting is a business - not a lottery. Do you understand the casting process (agents, casting directors, breakdowns)? Do you understand legal issues (contracts, unions, taxes, immigration laws)? Do you know effective marketing strategies (head shots, resumes, show reels, websites, social media)? Do you have industry connections and know how to network to get them? Basically - how realistic is your understanding of what is involved in attempting an acting career? It is like running your own company and you are the product to be marketed and sold. Will working as a MA be flexible enough to give you the time devote to an acting career? It's not like there are a bunch of open auditions you can just go to hoping to be "discovered"'or something.

To figure out if drama school is worth it to you - you need to figure out what you're really willing to do to attempt an acting career. Your question doesn't sound like you're willing to invest the time, effort and money needed for a professional acting career, especially because your chances of "making it" are so slim. It sounds more like you think it would be cool to live in LA and take some classes and maybe someone will give you a shot at something and that would be cool. That is extremely unlikely to happen - so it probably isn't worth it for you pay for drama school. Maybe if you were actually passionate about the work of acting and really wanted to learn the craft and the business and would be happy acting anywhere (even if it wasn't LA) - then it might be worth it. But your question seems to indicate you like the idea of being an actor, as long as you don't have to invest too much time or money in it.

But you might want to get a better understanding of the immigration laws and what is really involved in attempting a professional acting career - that can help you figure out if it's worth it for you.

Acting classes but no acting school? What do you think acting classes are--it's a school. If your too lazy for drama school then forget acting.

Nope, but your mind's made up. Good luck with that. I'm sure you'll be a great medical assistant because you're investing the time to be one.

1) Acting classes are held at acting/drama schools. That's what they do. You can't take acting classes without going to an acting/drama school.

If you're outside the USA, you won't be able to move to LA and work or study without all the proper documentation. And that's very hard to get. You would have to have enough money to support yourself, have a job already arranged, and very compelling reasons to go. They already have enough unemployed actors of their own.

But unless you study drama for several years, and get unpaid stage experience for many more years, no agent would even consider you - and without an agent you wouldn't get any genuine auditions.
On average, it takes about seven years of training and experience before an agent would take you on.

I act since I was 7. I don't want to be an actor, I am an actor. I wanna work in Hollywood. I believe that a job as a medical assistant will help me to survive and will give me the opportunity to take acting classes. And I wanna move to LA when I'll be 25-26. Now I'm 19 and I'll to a "part-time" acting school in my country. I'll put all my soul in medical school to become a great MA to be able to work in a LA hospital and all my soul in acting. I wanna live around actors and writers, thats all. :D
I have a lot of freinds in US married and on one had any problems with the law or with the visa. I don't know why I wouldn't get it. I think I'm a nice guy.

PS I'm a writer too.