[Sangetsu]

You will not have to apply for a new visa, you can simply apply for a change in visa status as shown in GoNative's post. Pay close attention to the contact that the English school gives you, it will probably be a one-year contract. You can't really be penalized for quitting early, but if they are providing an apartment they might try to deduct money from your final pay to cover breaking the lease agreement. Make sure you understand all the details before signing.