4 interviews, what should I pick?

Go on all of the interviews. If one of them offers you a job, then tell them thank you and ask if you could get back to them next week. Almost all jobs will let you wait a few days before deciding - and if they want to know immediately then the job probably isn't very good and you wouldn't want it. If they ask why you need time to get back to them (which they shouldn't ask, but many of them do) then just tell them you want to be sure of what you want, and that you need to discuss it with someone (your parents, sister, whoever), but that you appreciate the offer and will definitely get back to them.

By Tuesday, you will have had all of the interviews. Figure out which job you would like the most. If you haven't been offered that job by Wednesday morning, then call that job and pressure them, but be very nice - it is OK to tell them that you have had another job offer but you would prefer to work for them, and could they please let you know if they are interested in you or not since you have to make a decision and it is not fair to another employer to have to wait, particularly if your answer may be no.

If the job you want, won't tell you if you have the job, or give you some idea if you're going to be hired or not, then you'll just have to pick from the employers that did offer you a job.

It's perfectly OK to do this. After all - employers almost always interview a number of people for the same job and then pick the one they want - so why shouldn't you be able to do the same thing with multiple employers.

Just be very nice and courteous. And if you have to turn a job down, be very nice about it and thank them for the opportunity. You may end up working there some day anyway, and it always helps to be nice.