We brought our girls with us several times to AC and I'm sure during one of those times one of them had to have been 16 as they are 18 (19 this month) and 21 now. I'd also like to tell you that we have pretty dang good kids but even with that being said...
I would strongly suggest you accompany them everywhere. Maybe they can go off to gift shop while your in town doing lunch but you must give them boundaries in my personal opinion… and they should check in with you fairly often. When our family would go out for lunch, dinner... whatever, the young men would still try to "pick up the girls" with us being at the same dang table. Some young men are very persistent and you are not in the US! There of course drugs on the Island too, another little problem you/they may have to deal with. ;-)
Needless to say, our girls never left our sides during any of our trips to the Island!
Although I could have done without the bubble night when I took the eldest clubbing one evening... try to find your kid in a room full of bubbles! IT'S DIFFICULT TO SAY THE LEAST! I shoulda sent the hubby that night (coulda saved me a cracked rib too if he went instead!) HA