5 is NOT old for a parakeet. They can VERY easily live to be 10-15 years old and some even live to be 20. Your parakeet is only mid-aged, not old at all. Birds have very long lifespans, and birds larger than parakeets, like cockatiels/conures/lovebirds/caiques, etc can easily live to be 20-30 years, and larger parrots can live into their 40s, 50s, 60s, and even 80s, some into the hundreds. Your budgie's beak color doesn't sound like anything serious, but if you are concerned, I recommend calling the vet up and asking.