Offered a job but need to decide before another interview?

So, I've been on the part-time job hunt for awhile, before the new year, as a student. I think I do well in interviews, I just was having a lot of trouble getting to that stage in applications.

I finally got an interview last week, and they called today to tell me they wanted to hire. It's part-time, usually the shifts go into the evenings, 15-20 hrs a week from Thurs-Sun. $18/hr. The people were all really nice, but they want an answer by 4:30pm today (5 hours). The job seemed alright, somewhat relaxed, but parts of it seemed different than what I was expecting. I'd be in a movie theater asking people what they thought if new releases, but I also have to audit things like their gender, ethnicity, etc. and overall just be a little annoying (as I have to interrupt people) in order to get those surveys.

Then, I have an interview scheduled for Friday, which would be for a position that I believe, and was told, that I would be a verys torn candidate for. I am really into filmmaking, and I would be able to teach youth fill production 2x a week, for about 8hrs/wk. I have a lot of experience in instructing kids, and I do think I have a good chance at successfully getting this position.

Now, both would work around my school schedule, and I'd make more money at the first position (I just might feel a bit gross), but unfortunately I can't decide fully on both as I have to choose on the first job before my interview for the second. What should I do? I could even do both at once, but that might prove to be a lot. I already have classes four days a week.

Thanks.