The first one is the most correct "It's already midnight now!" but it would be more common to hear someone say "It's already midnight!".

Yah Yah it's already midnight and my girl friend waiting for me

Thanks for your help.

It's much more common to simply say ''It's already midnight!''. In this sentence, ''already'' and ''now'' are a bit repetitive.

No, you don't need the ''the'' in this case. So, the correct one is ''It's already midnight now''.