I am glad you want to go and make a heavyweight robot, but have you thought it through, to have such a monster requires a lot of money to run and even without any weapon they are potentially lethal!
A 100Kg robot is heavier than most men, and it takes two men to lift them safely, poorly wired electrical weapon (axe) and it operating when you don€™t expect it too, the result would be very serious, I would not start such a project until I was at least 18 years old with experience with feathers for at least two years. I know you don€™t want to here this but without dampening your enthusiasm 13 years old is not quite old enough for heavyweight robots. Sorry