I have no ill will toward the deal between Pakistan and China; I'm simply stating some well-known facts. The Chinese military has always been low-key about arms sales, and they won't acknowledge any such transactions until the very last minute. Therefore, your claim that an agreement has been reached is not very credible.
The fact is, China currently has a significant need for medium-sized stealth fighters, and equipping its aircraft carriers with a full complement of J-35s is currently the top priority. China wouldn't export its latest military equipment; the J-10 served in the Chinese military for nearly thirty years before being exported. We have no reason to believe that China would export the J-35 immediately; it defies common sense.
I predict two timelines for J-35 exports:
1. India acquires advanced fifth-generation fighter jets and gains an advantage over the Pakistani Air Force;
2. The J-50 enters service.