Jump at the chance mate, follow Kals advice of course, but theres a lot of pro's in any job out there that fight for chances like this, it might end up being nothing but experience for you, but you cant beat experience.
Worst case scenario, you take some time out of your day, learn some do's and dont's of this type of work, nothing comes of it, shots aren't used, noones any the worse off but you have learned a bit more about it.
Best case scenario , you take some time out of your day, take a couple of cracking shots, lady is a headhunter for Adidas/Nike/Puma/Airwalk, you fall into a job that has you working with leggy models wearing sports footwear that pays a 6 figure salary, the rest of us Hexites are green with envy and refuse to talk to you again.
its Win/Win