I wouldn't bother with Vegas/most of the US until your 21.
You can't drink or gamble so it takes out a lot of the fun. Plus they can be really aggressive with "moving on" minors. First trip there I was 9 and my brother 12, but they were so angry about not letting you even look at the gambling areas. Fairly obvious we weren't trying to sneak in/gamble, so it was rather stupid. My cousin went with his friends after their HSC (they did a US trip, not just Vegas), and he said it was good but because you look young they get really strict :/