OK so I just started using Cloudflare. My server has a Letscrypt SSL and I have it configured to redirect all HTTP request to HTTPS.
I also added this HSTS header:
add_header Strict-Transport-Security "max-age=15768000; includeSubdomains; preload;";
Now I would like to enable HSTS on Cloudflare as I want to use its proxy/CDN. Is this OK? Can I do this? Is it recommended I do? Anything I should worry about before I apply it?