You have been mis informed Jord, however i did leave 10+ yrs ago. We were under attack in west belfast and waiting to be crashed out when someone said who the fook are you to some new guy, he had just finished his training a few weeks, if that, prior to his 18 birthday and was now in our platoon !!
It will also depend when your unit is next due to do a tour. You can, in theory, go straight after you complete basic training. However, unless your unit provide very, very, very good build up training prior to you going (and I am talking months here, not weeks) don't even think about it.
There are blokes mobilising now for Herrick 10 who did CIC in July. As someone else has said, it really depends on you unit's next tour. Patience is a virtue, if nothing comes up soon dont worry- it will. Do as many weekends as you can esp in the field or live firing, no matter how bone it may seem.