everybody is different. your body is totally done growing by age 25. i know most is done before but as far as bone structure or anything else 25 is it. an exercise to make you grow bigger (though probably not you balls lol)is breathing squats specifically 20 reps in arow with a weight u could do 10 reps with and u add 5 pounds every workout. im sure nobody here really cares but im doing this so thats why im passing it on. the combination of these exercises literally expand your rib cage(under 25) and a bigger ribcage allow you to pack on more muscle. not to mention the cardiovascular and circulatory benefits.