I don't know how to describe my character.

Maybe,in my classmates' opinion,I am quite and shy. Even sometimes I agree so.But sometimes I dare to do something that others afraid to do.
I am always afraid to raise my hand in class,but I don't know why.However,I dare to give a speech in front of three thousand students,the whole school.I even have ever joined a singing competition and have sung a song in our school.
Most students are afraid of their teachers, so am I. But when my teachers did something wrong,I would give them some suggestions.If they did something terrible,I would criticize them in a right way.
And if I go to an amusement park,I will ride the roller coaster first.
Am I a strange person? Do you know how to describe my character?

p/s:i think it is normal :), many friends is similar.