15 years is very over-ambitious, so is "sea control of the Western Pacific" which is rather vague. There are many more countries in the region than just China and the US, with the significant military powers among them being US allies such as Japan and South Korea.
It would be very ambitious for the PRC just to try to roughly catch up with the US lead in deployed military technology in 15 years time, even only within fields the PRC needs, and maintain current force levels. This includes ships with railguns, SSK/Ns, SSBNs, stealth aircraft manned and unmanned, hard kill lasers, SAMs, ABMs, ASBMs, all sorts of PGMs, radars/sonars/sensors, EW equipment, nuclear deterrence, etc.
It is also very ambitious for the PRC just to aim for control (both air and sea) of the "Western Pacific" area immediately surrounding the PRC within the first island chain with the ability to bombard at will Taiwan and its vicinity including all its surrounding seas. Just that would be sufficient to discourage Taiwan independence, subject foreign intervention forces to attack in case of Taiwan independence, and for the PRC to mount a military operation into Taiwan.
Well, we all know how China sets really low and unambitious targets for itself. Plus it also depends on how large China's economy and military spending grow to.
Plus the exact timeframe I mentioned was "15+ years"