一小段英文,求修改找错Most of the time,I wanna change my nature,and try

most of the time,前面加一个at,at the most of time
你改的应该不是天性,应该是性格吧,用character会更好一些；
keep me in good humour,应该把me改为myself；
I need do中间应该加一个to
later是什么意思呢,是以后吗?如果是的话建议用from now on“从现在开始”
还有就是这句话是书面的呢还是口语呢,如果是书面用的话建议把wanna改为want to,或者would like to,如果是口语的话当然wanna更好一些

Most of time,I wanna change my nature and try to be as humourous as possible.However,at present, I think that I should stick to my own personality and do what I desire after my eighteenth birthday .

At most time I wanna change my nature and try to keep in good humour,but now I think I need to do what I should in my own way .I am 18 years old now.