Let me give you one advice that if anyone gives you topic then that topic will be difficult for you to learn and even to remind and speak. you can't learn all of lines. but if you have written topic of your own then you 'll be able to learn it fast than other topic given by someone. if you even forget a word even then the main summary will be in your mind and you'll be able to speak without stopping. so I just want to say that you should write on your own. it has two benefits
if you'll forget something then you can remind in just a second.
and your writing skills and grammar will also get improved.