What will happen if you do 500 sit ups every other day 150 slow squats and lift a 2.3 wegiht on your arms 3800 times if you are 15 and 60kg and 5.8 ft?

you will get ripped. seriously. but if you're trying to get big, you might consider trying more weight and less reps for the arms

Yeah you're tall for your age but you won't have the will to continue. You can't just start with 1000 reps and expect to carry one. Start slow and build on when you have the strength to. It doesn't come over night.