DJ Legality?

I’m planning on DJ’ing a small party of a hundred or so people in the near future. I was thinking i would just bring my sound gear and CD’s. I’ve never done this in a “public” place before, its just been in peoples houses and such in the past.

I was wondering if there’s any restrictions on playing just anything in a public place like this, or if i need a public license for all the music i plan on playing or something like that. Does anyone know anything about this kind of thing? I bought all the music i have, is that good enough?