So I have noticed that other people have been offered interviews already. That is making me worry a little. I haven’t received an email yet so does that mean my application was not as good? Do they send out interviews based on the quality of the applicants applications? I know it’s not because of limited interviewers because my friend who lives in the same area was offered one as well.
No, they base whether you get an interview on the availability of alumni in your area/at random, don’t worry 
They have a list of people in each area and they’re simply chosen at random by the interviewers
Does that mean I will never have an interview opportunity with Columbia since it appears that they have already sent out interview requests?
I did interviews for Columbia for years but stopped because I felt like they really had no impact. They are based on geographic availability and have nothing to do with the qualifications of the applicant. The only place I could see them hurting would be if an applicant was really off and the alum decided they shouldn’t be considered, which in my experience is exceedingly rare. The way it works is a regional chair coordinates interviewers who will get a number of interviewees assigned to them. Sometimes the interviewer does a good job of reaching out and sometimes they don’t. They try to have the interviews wrapped up by mid-February but even if you have an outstanding interview, I doubt it tips the balance. Obviously things may change but I wouldn’t stress if you don’t get one. A large number of applicants don’t. (And you still might get one).
I just got an email for an interview like 2 days ago lol but I was hoping for a cornell interview and their deadline to send in the interview is coming up so idk if I’ll get a cornell interview. But I got my Columbia interview request really late