Is ETHZ really very hard

Honestly there are really cool universities in Europe where you can learn much about Computer Science and related subjects.

If you look at the rankings of universities in the world you will see that ETHZ and EPFL are ranked among top 50 unis for CS subjects. Last time I checked ETHZ was somewhere around 7 and EPFL somewhere close to 20. However keep in mind that the rankings are important for future employers but not that important in terms of teaching. Wherever you go in Switzerland and Germany you will face the same approach to science, with top class professors.

Let me clarify some stuff for you, first of all tuition fees in Swiss are not around 500-600 euros! They are a bit higher, however the real problem with living in Swiss are the living costs. I hear it is damn expensive over there. Especially if you think about Zurich.

When it comes to Germany, the semester fees are less than 300 euros. So you will be paying at mos 600 euros per year for studies. In some federations of Germany you even get a semester ticket, which you can use for traveling for free by bus and by train withing the borders of the federation where your University is located.

It is true that all the programmes offered by universities are not completely in English. However the selection of courses which is provided for international students is pretty nice. Additionally, at the moment there is a lack of IT people in Germany. My professor said "The only way not to find an IT job in Germany is to die early". If you register for master studies in germany, the state requires you to have at least 8000 euro in bank for 12 months. So they have calculated that as a student you can live comfortably with that money. However, you are free to spend as much as you want. This is the minimum that I told you.

If you are interested for English studies, bear in mind that Sweden provides CS studies mostly in English (over 80% of the population is fluent in English over there).

I think the main thing that you have to consider when registering for your future studies is the difficulties that you will face due to "poor" background at the moment. Studies will be very demanding (I know it form myself, I've been in the same position), but with hardwork you can achieve everything. However, if you are not ready to invest extra time to your studies, do not bother going to ETHZ or EPFL, or top universities in Germany.

I hope I answered you question, if you have further dilemmas let me know.

Edit1: Since you are aware of your drawbacks coming from the Bachelors, analyze well the curriculum of the university where you are planning to apply, and before that make sure to watch some of the free courses (related to that curriculum) provided by top universities online:

The courses provided in Masters studies are usually a continuation of the courses from the Bachelors, so check what the students have studies during bachelors in the unis that u are planning to apply

Selam ;)