It depends on how large the weights are....
Best to start out with a weight you can lift for 10-12 reps. As you progress you can lower the reps to what feels most comfortable. Everyone is different, and some can start heavier, but 10-12 reps is a good place to start.
Yes, this is old enough. Lifting will not stunt your growth as the myth grows. Just make sure you do it correctly, and get supervision at first.
you should be at least 12 years old.
it really depends on what you want as the results...big heavy muscles...heavy weights..nice looking muscles..but slower, light weight lol low weights and high reps give you lean muscle, you may not see it if ur not flexing but when you do its there. heavy weights and low reps give you big bulging muscle and isn't really defined at all. high reps are usually 12-20. low reps are usually 6-8.
around 12 years old
It's all normal to have man boobs at any age. The way to get rid of those are to lift weights and exercise and after a while you shall be all cleared and flat on the chest.
It depends how heavy boned you are.
At 12 years old, it is not recommended to lift heavy weights like 1.5 kg without proper guidance and supervision, as your body is still developing. It is important to start with lighter weights and focus on proper form to prevent injury. Consider seeking advice from a fitness professional or your doctor before starting any weightlifting routine.
Yes, this is old enough. Lifting will not stunt your growth as the myth grows. Just make sure you do it correctly, and get supervision at first.
Exercise does not stop you growing. Running,cycling, swimming etc are all healthy examples of exercise and don't stunt your growth. Lifting excessively heavy weights at a young age (12-14ish) however, can stunt your growth and effect the development of your arm muscles and bones. If you plan on lifting weights at an early age you should ask your trainer/coach for advice and stick with smaller weights. To be honest, I would just recommend push-ups, pull-ups etc.
I believe this answer depends on one's height also..