"Noi avem două materii noi semestrul acesta."

Translation: We have two new subjects this semester.

[Abidaga]

In British English, the word "semester" is not as widely used as the word "term" (although its usage is increasing). Could I suggest considering allowing "term" as an alternative translation?

[DornenEngel]

I know it is not a 1:1 translation, but I am of the opinion that:

We have two new subjects in this semester

should not be considered wrong.

[Wes708337]

As an English speaker, it sounds wrong to me, so I wouldn't suggest using your translation.