It's a top-tier talent tho' not beyond that IMO...and boring. Boring boring boring. Traits are best as a reminder of your background and this says nothing about you.
It's pretty strong, since you can trade odd number to odd number and get an ability bonus with no penalty. For instance if you have a 17 and an 11, you could turn that into an 18 and 10, so the 18 netted you a bigger bonus, while the 10 is mostly the same as the 11. It's why almost all ability modifications in official pathfinder are multiples of 2.
If this stacks with the normal racial bonuses it is way too strong. With this I can get a starting stat of 20 for 14 points instead of 17. Getting an extra 3 points to purchase stats is too strong for a trait.
It depends on which rule set the game uses for starting ability scores.
If your game uses point buy, then as a few have already pointed out, it is VERY strong... a bit too strong in fact... +1 to a single ability score may not seem like much, but with point buy that +1 could free up 3 points to spend elsewhere, effectively granting them as much as +4 spread across all their ability scores at the cost of only a -1 to a single score.
If your game uses a stat array, then it depends on the array in question... in a game using an all even stat array, this trait would serve only to give a player a little more flexibility with their ability scores, though nothing particularly game breaking would come from it, such a character wouldn't really see any real benefit from the trait until level 4, and every 4 levels thereafter. On the flip side however, if the array has 2 or more odd stats in it, this trait can give an early power boost with no real downside.
If your game uses rolled stats, then no, such a trait would not be overpowered by any stretch of the imagination. With rolled stats, this trait would serve mostly to aid those who had some bad luck with rolls, letting them move some points around. Someone who rolled really good would in all honesty have no more or less benefit from this trait than someone who rolled really poorly, and as is the case normally with rolled stats, the attribute spread variation from character to character is usually all over the place by so much that someone spending a trait to get an extra +1 at the cost of a -1 isn't going to make a difference.
I'd say that with rolled stats it could make just as much difference as with point buy, or perhaps not (as it's random). Depending on how the numbers fall, it's either a free +1 bonus or it isn't. One of the last characters I rolled (a sorcerer) ended up with something like a 27-point array, except that every stat was odd. Another PC in the same campaign had all but one even.
As it's only physical stats, it has a 50% chance of being a flat bonus and a 50% chance of being an effective +1/-1. Which means that to balance it, it should really be either +2/-0 or +2/-2 to be the same for everyone. Which shows how good it is.