Pointed, protruding ears exist in mammal species because they are better for 360° hearing, whereas our ears are better for hearing from the front but not so much behind. So, put your elves in an environment where hearing in every direction is advantageous (e.g. natural predators).
What causes aging?
The effects of aging are caused by cell senescence. Every time a cell undergoes mitosis, the telomeres on its DNA get shorter (telomeres are like a protective buffer segment that doesn't actually store any information). When these decay enough and the important DNA starts getting damaged, the body tells them to stop dividing. But, they do continue metabolizing, taking up resources and acting incorrectly. Sometimes they even start dividing as fast as they can, which is known as cancer.
Like having pointed ears, there are some animals that age very little, if at all.
In naked mole rats, the cellular senescence mechanism doesn't just halt mitosis, it tells them to shut down and die so they can't cause any problems. This makes them more-or-less ageless, and also quite cancer-resistant.
In lobsters, the body continues to generate the enzyme telomerase, which causes telomere regeneration, throughout adulthood. In other animals, telomerase production stops after the embryonic phase. So, lobsters' telomeres never decay, so their DNA stays in pristine shape and they don't age. That being said, cancer cells also rely on telomerase to divide indefinitely, so they don't get the same cancer resistance as naked mole rats.
Something you'll want to consider though is why they live longer. There's a reason why natural selection didn't cause age prevention to evolve in most animals—it doesn't help population proliferation. Elves will need to continue having children throughout their entire lives for such long lifespans to make sense from an evolutionary standpoint. Family trees might look a little weird.
This could even tie into the predator presence mentioned in the section on pointed ears. Maybe they keep reproducing because they take a long time to reach adulthood where they can adequately fend for themselves. If elven parents don't stay with their offspring for that long, many will not reach maturity. Hence the need to keep making more.