Your school is giving you the right advice. In 2026, it's still going to be computer-based only, with no exceptions and no plans to go back to paper. Even if you have vision problems or other issues, you take it on a computer - just with font enlargement software or in a separate room. There really are no paper versions.
But the main thing is not just to get used to the screen, but to practice actually solving problems on a keyboard and mouse. A lot of people take practice tests at school or use open test versions online, and that's helpful. Here's the thing though: don't waste time memorizing the interface of FSEG's testing software. Instead, learn to write code in a regular IDE (Pascal, Python, C++ - whatever you're studying), because that's what develops speed and logical thinking. The exam interface is intuitive; you'll figure it out in five minutes.
And here's a lifehack: if you're studying at home, occasionally solve problems without any hints or autocomplete in your IDE, so you don't get dependent on the compiler's help. On the exam, it'll show you errors, but you'll have to fix them yourself, and that can eat up time if you can't quickly read through code in your head.