Not sure if you're flying electric or other and is your trainer rudder or ailerons, whichever though do think it's a huge step up. I've 3 times destroyed a Mustang and am now flying a 3D plane on reasoanbly highish rates but it's probably more forgiving and predictable than the warbird. The time to move up a plane is when the one you're flying you've upped the throws quite a bit, played around with and moved the C of G back to make it more responsive and having made the changes you're "throwing it around" in the sky, ie pushing the plane to the limit but also not thinking but knowing if you've got it wrong you can correct it easily.
Are you rolling the plane / able to fly and hold it inverted with confidence and other aerobatics, if not you've probably got a lot of mileage / stick time to go and even then the warbird will be a big jump. I was at that stage with a Multiplex Minimag, decided it was time to try the Mustang again, 1st flight absolutely beautiful had me grinning from ear to ear, second flight don't know what caused the wing to drop, think as it was all happening so quickly I corrected the wrong way which made it worse and the panic was there, too many bits to pick them all up so just grabbed bits with motor, servo's and battery attached !!!!!!!!
Hope that's of help !!!!!!!