Some old-timer tips: also keep the INSIDE of the windshield squeeky clean. Meeting on-coming traffic, focus on the shoulder right and away from the approaching lights. Some of my (ahem!) more elderly friends swear by clear polarized glasses - I've never considered them for night use but they sure help cut the glare of the water surface when fishing.
As for age, time waits for no one. I've had problems seeing the white center stripe on wet roads for as long as I can remember, especially if there are any oncoming lights - even those too far away to really affect you directly. The shoulder stripe, if there is one, is almost always easier to see. That 'deer in the headlights' fascination with the approaching lights is likely the biggest problem - you are looking only for the center line and that puts you looking straight at the approaching headlights and their glare. I wouldn't blame the Jeep windshield particularly unless it's a simple question of proper cleaning.
Bill H. Notes some similar tips later > i realize this, and will go about ten under if i need to, but either way if