Hi, Daniel! :) 

A. If you were a song, what song would you be and why?

I would be a conscious rap. ✔

Because I prefer rappers who talk about their biographies and some social issues to of rappers who talk about their brilliant life.

B. Make these sentences into English:

(02/23/22)

-기다려, 내가 가서 사 올게.

Hold on, let me go to buy it. -> Wait for me. I'll go and buy them.

=> Corrected : The sentences are corrected grammatically. 

-아냐, 같이 가자.

No, let's go together. ✔​

-사람들이 줄을 서 있어.

The people are lined up. -> People are standing in a line.

=> Your sentence has a correct grammatical structure, but this has the correct usage/ expression.