You're Correct!

Placing the golf ball in the right position is one of the most under practised skills in golf, whether during the set up of the full swing, short game and especially putting.

The correct place to position your golf ball is just ahead or forward of the centre point of your body. This is because the centre of your body (nose, sternum, belly button) is where the bottom of the swing arc is for your putting stroke. By placing your ball here you will have the best possible chance of striking the ball on a very slight up swing as the putter moves past the low point (bottom of the arc).

Striking the ball in this way will produce an impact with the optimum amount of over spin to get the ball rolling on top of the green much quicker. This will give you the best chance of becoming more consistent because you will be able to control the distance of your putts more. To make sure you get your ball position right you need to have a pre-shot routine that you repeat every time, so follow these steps to make sure you get it spot on every time you putt:

Move into the ball keeping your feet together, make sure that the ball is directly opposite the big toe on your front foot. Now place the putter behind the ball. You should note that the face of your putter is in the middle of your feet.
Now you must move both feet the same distance apart, and roughly shoulder width. This will give you a nice, solid base, especially if the wind starts to blow.

If you have followed each step correctly your ball position will be an inch or two forward of your centre and you will be able to roll your ball along your intended line towards the hole more consistently. Take care to make sure you repeat the steps, ensuring your ball position is constant every time you take your set up.

If you place the ball behind the centre of your stance, your putter face is then too far back in your stance, meaning your impact with the ball will be before the putter head reaches the low point of the stroke. This will create a downward angle of attack resulting in you hitting the ball into the ground, causing it to bounce before it starts to roll.

Placing the ball inside your front foot moves the putter face too far forward of the low point of your stroke. This will not only create inconsistencies with where on the putter face you impact the ball, but also the putter face could potentially be starting to look closed to the target resulting in missing too many putts.

If you have the ball outside your front foot, you will launch the ball too high as your putter makes contact with the ball to much on the up. Your hands will be behind the putter head at this point causing a very inconsistent impact. The ball will also have a greater chance of being deflected off line by the spin imparted by the impact.