I would like to know if there was a special prayer and/or duaa i could perform before an exam ?
I usually start my exam with Al Fatiha.

Also, I would like to know if I am allowed to perform Tarawih with sunni people (so in groups) since I do not speak arabic and can’t do them at home alone.

http://www.duas.org/student.htm

Shia do not pray Tarawih because it is not in the Quran or the practice of the Prophet or Imams.