I am superheroine and my siymbol is a black thunderbolt.

By "thunder" did you mean lightning bolt? (They can also be called "thunderbolts") I'm not quite sure. For reference, this is what I think you meant: https://tse1.mm.bing.net/th?id=OIP.8NOSdbw12tvGJWxpfyFp1wHaHp&pid=Api&P=0&w=300&h=300

My costume is all black like a dark, with a white thunderlightning bolt on my chest, and I also have a black mask that only covers half of my face.,

I'm not sure what you meant by "with a dark" here.

Bbecause I don't want people to see and recognize me.

Better to link this part with the previous sentence.

My powers are simple I am able to think, act, move in mere seconds or less, far faster than normal people could think of.

Just added a word for the flow.

I also have weapons because my powers aren't strong enough. (on their own). I have weapons all over my body like a simple handgun, battle staff and bracelets that discharge electricity. People didon't see me because I only transform when the last sunlight sets and the first rays of the moon come outfall.

1. Added a phrase for flow (the one in brackets)

2. One usually says "rays of X *fall*" (depends on the dialect though)

I have many enemies, but my worst enemiey is Quicksilver.

He takes electricity from neighboring cities to keep the whole world in darkness, but I stop him from doing it every time and sometimes I win and bring electricity back to the city, but I think he will never stop until total darkness comes intovers the world.

Changed a word because it sounded more natural.

I am a superheroine and my siymbol is a black thunderbolt.

My costume is all black like a dark with a white thunderbolt on my chest, and I also have a black mask that only covers half of my face.

BThis is because I don't want people to see and recognize me.

My powers are simple: I am able to think, act, and move in seconds or less; far faster than normal people could think of.

I also have weapons because my powers aren't strong enough. I have weapons all over my body, like a simple handgun, battle staff and bracelets that discharge electricity. People didon't see me because I only transform when the last sunlightsun sets and the first rays of the moon come out.

I have many enemies, but my worst enemiey is Quicksilver.

He takes electricity from neighboring cities to keep the whole world in darkness, but I stop him from doing it every time, and sometimes I win and bring electricity back to the city, but I think he will never stop until total darkness comes intotakes over the world.