YOU SAID:
I can't believe that i am done high school now thats so exciting
INTO JAPANESE
私は高校を卒業したとは信じられません。
BACK INTO ENGLISH
I can not believe that I graduated from high school.
INTO JAPANESE
高校を卒業したなんて信じられない。
BACK INTO ENGLISH
I can not believe that I graduated from high school.
That didn't even make that much sense in English.