kate always goes first

They both seem okay. Whatever you choose man.

i want the public's choice.

No this is the proper way, I am an armature in English, do it right! lol It makes it look more professional and is easier to read since this, "hi Kate!" always implies speaking.

i prefer this way because then u could know who says what first rather than finding out who says what at the ending

Damn, no offense to anyone here but what the hell are they teaching you all in school these days? lol Maybe it is just the fact that I am a really good reader and can determine who is talking in the story without reading the end, but that is just the way I am. I have read hundreds of books in my lifetime and some of them more than once, have had lots of practice.

Same as Katealphawolf.

It would be:

"Bla, bla, bla," said Kate.

The other way is more script-like, which is also fine if that's the format you want to use...but if you're writing in regular narrative prose and switch to that style when the characters speak, it just seems very...improper.