Should I try to compete in prelims at a contest some time soon? Maybe guidelines would be helpful . . Thanks!
Really, you should, unless you have nearly no experience. At worlds this year I realized I could have competed and done just fine (By that I mean top 75, as Most that rank higher get destroyed because of nerves, which I dont really have) So Go for it man and do it to have some fun!
Here is a basic guide to assembling your freestyle-
If you feel you’re ready, go for it.
Learn to make a 1 minute routine, show off your best skills, sync it to music.
Worse case is you’ll find out how you compare and hopefully figure out what to work on.
So, start downloading routines, get ideas, see how the name players do it. There’s also a lot of preliminary videos too so you can see how people do in those.
I think I’ll try when I’m ready. I’ll try to make a routine, watch some videos etc. . . I’ll go at my own pace. 
Thanks!