I had a major braking issue years ago, can't be arsed to explain, but turned out to be faulty braided lines.
That aside, braided lines will always have a better feel than OEM lines, once sorted correctly, and bled properly, to the point of being incredibly responsive.
Over time (years) original lines can have weak points, and eventually expand when braking, a bit like grabbing a handful of a balloon where the excess bulges where it can, so braking will lack response, or feel spongy.
This is one of those things that can very slowly creep up on you, and once fixed your braking will be exceptional in comparison, as long as your pistons are moving correctly too.
So even with your low mileage a swap to braided lines will be a huge improvement, along with new fluid as well, and you can expect a massive difference.
If you're not a heavy braker there is a fair chance your lines could be okay, BUT, 12 years is a long time for anything, so it won't hurt to replace them.
They can only improve things.