Not at all. It's purely a matter of preference. The Arduino style happens to be the second style ("1TBS").
Worth noting that, although the classic Arduino IDE's Auto Format tool allows the user freedom in the brace style they use (which usually ends up being a completely random mixture of the two), the new Arduino IDE 2.x's Auto format currently enforces the "1TBS" brace style, meaning that if you want to use the Auto Format tool you have no option in the matter.
So you might use that as support for your case to your teacher to allow you to use the "1TBS" style.
On the other hand, you might realize that annoying the person who is grading your work is not the wisest choice and comply with their formatting preference.
I think it actually may be a valuable lesson. When we're working on our own projects, we have freedom to do as we prefer. However, in professional, or even many hobby/volunteer open source projects, we have to effectively collaborate with others. If everyone stubbornly uses their own preference of formatting style, the code turns into an absolute mess. In this case, consistency trumps personal preference every time. You could waste a lot of time trying to convince the rest of the team to switch over to your preferred formatting style, or you can just go with the existing convention and get right to making things happen.