While I try to be the best I can by practicing accuracy as much as speed, I would expect a handgunner to hit at least a standard 9" paperplate at 25 yards with a service sized gun, unsupported, kneeling, and prone, 10 rounds each. Time limit of 3 seconds per round.
If you want to be good, you will have to do better. Do some competitive shooting and find out if you will be better than average.
One of the things that I think of most is the difference between shooting as you describe and how a real-life SD shooting typically occurs.
For an armed civilian, I'm willing to bet that "9 inch target... 25 yards... service size gun... kneeling... prone... 3 seconds each" are situational elements that are never going to take place in a dark alley, or a deserted street at night, or the far edge of a parking lot.
"Target practice" is fine for people just learning about handling a pistol, but self-defense in the real world is all about "Fast draw... point shooting a short barreled pistol... using cover... 3 shots COM
within one second... shoot until the threat disengages..."; those kinds of things and more variables that are possible but can't be determined beforehand.
I'm truly not trying to be argumentative here, but shooting to a certain degree of accuracy is moot if it's done at a target range.
What the OP might look into is to enroll in one of the defensive shooting schools offered in most cities. That's where many of the things that an armed civilian can be learned that will give him a better chance to survive an armed encounter.
"Target shooting" is fun and can be done until you can knock the balls off a flea at 100 yards. But what will save your life is an entirely different set of skills where "accuracy" is only one variable among many in a SD situation, and it's not even that important considering that the target is almost always way too close and plenty big at that range.
If you miss COM, it's not because your accuracy is off, it's because your shaking with fear, and that's something you can't overcome by shooting said balls off a flea at 100 yards.
Even police officers who train for such encounters often miss their targets at close range. Ever wonder why, if they can do so well at "the range"?
I'm just trying to answer the OP's question in a practical way that he may not even understand himself how his question applies in real-life.