Las Vegas for a Sweet 16?

So I have just decided with my parents that for my Sweet 16 our family trip will be to Las Vegas. (We have a timeshare so it won't cost that much and it's in place of our regular trip to Florida) So I definetly want to see Garth Brooks (he's why I really want to go! It'll be my first concert and he's my favorite singer!) and the Dolphins at the Mirage. We'll also see the Blue Man Group (saw them in NYC and Orlando already). :) But I'm worried about a few things- Is Las Vegas safe? Does JFK have full body scanners? Is it common for airplanes to crash? Is it more likely to die in a plane crash than not? Does JFK have full body scanners? How long is a flight from NY to Las Vegas? What's the weather like? What are other things to do in Las Vegas? Is it a good trip for a family of 5 youngest being 10? Thanks in advance!