you'll be going to either ADC Bassingbourn for approx 22 weeks or to AFC Harrogate for 42 weeks for your basic training as a junior then off to do your trade and combat engineering at Chatham and Minley.
My son just passed out from his year at AFC in August and loved it and the lads and lasses you'll be in with will be around 16-17 year olds. Its longer than the 14 weeks adults do to get you all in at a steadier pace and the educational, sporting an advenurous training packges are great. Ask your recruiter if he has the AFC DVD you and your parents can look at if you havent seen it yet as it gives you a good insight. Good luck at ADSC and hopefully you will pass in time and places are still available.