Longer days should start them laying, ideal about 14 -16 hours of daylight. You can supplement this in the winter with artificial light if you want them to start laying.
Layers pellets work well but I used to supplement them with an extra bit of protein from some cheese or hard boiled egg, and few extra vitamins (a drop or two of my children’s Haliborange in their water worked just fine).
Sexing was easy, after a few months the boys started to crow in that strange strangulated call. But there are some good pictorial guides on the net also. Age of a quail? The only way I can think of is to look at the beak and feet, young birds should be softer, less knobbly.
Good luck and remember you can always threaten them with the BBQ, they taste very good.