Shiny/nature abuse and IV abuse occurs at different frames unless you just happened to pick the same frame, lol. So this case, your frame is 13. Just use elm to verify :) You can read Riski's help guide and it has pictures on how to use Elm verification the easy way to not have to physically count 12 elm calls, lol.
Good luck!
It will be very tough for you to get the info right without an AR though. You can maybe try and rare candy up...but yeah...it's risky nonetheless. I wouldn't save unless you can do save states, lol.