I'm a high school graduate with no direction in life
Why do you feel that you lack direction in life?
I feel like I'm going to ruin my parents' lives
It's okay to not know where you are going right after high school.  It can take time to figure out what you want to do, and your parents understand this.  You will not ruin their lives just because you take some time to figure out your own path, they will be proud of you no matter what.
What if I fuck up my parents' lives?
Do not worry about fucking up your parents lives. Your parents will be happy if you are happy. Just do your best to live a happy life and to find out what makes you feel fulfilled.