I've had lifelong ptsd and it's ruined my life
What gave you such bad PTSD?
When I was 13 my parents decided to walk out on me and my siblings.
It's understandable to suffer from PTSD from such a traumatic event in your childhood. Untreated PTSD can have lifelong issues which can cause you great stress and harm. Reaching out to someone for help in order to treat your PTSD is a great option to take in order to start healing.
I don't need treatment because I'm cool with it.
I still think that you might need to talk to someone about it. If you feel the need to bring it up so much, it might be safe to say that it is still bothering you.