at that age its really hard to grow more... im 6'2 and 18 i drink about 1L of milk a day and i used to drink more but i havent grown for like 1and a half or 2 years now. i think milk only works if youre younger because im three inches taller than anyone in my family(short family lol). but i think stretches can help u. back stretches. its something about the vertebras on your spine that can make u gain a few inches