教室 - classroom
Because きょう (教) is the Sino-Japanese reading (the onyomi) of 教える (おしえる), "to teach". And しつ (室) is just "room".
another easy but slightly more native sounding way to say this is: "教室に行きたいんですが”
Which literally means "I'd like to get to the classroom but..."
Japanese people are quite indirect and often ask for things without actually asking for them ^_^
Note however that 何処/どこ is usually written in kana only.
The perpetual question.
The question I asked perpetually in college.
I wrote " Where is the class " and it wasn't accepted.
I have such a hard time remembering words when I see them in kana only. It's why I wish more kanji would be introduced at this stage.