Yes you should worry.

Technically here, you don't "qualify" until the miles hit...together with the record that AA has re: their miles posting for MPC (anywhere from 4-25+ days I've found, very inconsistent: I'm currently waiting for AA miles flown over a week ago to post, and distinctly recall one once the miles not hitting for more than 3 weeks, and also twice where they just never credited at all), there's a very good chance of your fear happening. As you know CX credits their miles pretty quickly, even from outports. Kinda a pain in the a$$ that they have this clause whereby it's when the miles post, and not when the miles are flown. Adds an unnecessary random element to the program in my opinion.

What you can do is this: You can wait and check your MPC account right before your transpac flight. If the AA miles haven't posted the few hours before your flight, you can remove your CX# from your CX transpac flight so the AA miles guaranteed credit first. Then, do a missing mileage request for the CX flight.

I think you should probably consider this, since you're going for GO...hence even if you're sure you can make GO next year, there's always the chance your travel patterns will change and then DM comes into the realm of possibilities. You certainly will be kicking yourself next year if you're at 113k because those AA miles posted late.....

If you decide to risk it, you always have the chance that CX will be kind next year if you just miss GO or DM and grant them to you anyway since you got caught in the randomness of the MPC mileage posting clause. It sounds like CX has given a number of people DM who didn't hit the threshold this year out of goodwill (aka, terrible economy), however, and I'm not sure if next year they'll be so generous this year given the economic rebound.