If you are very petit - you may have to scale it back a little. The elderly often find it difficult to drink larger amounts of fluid - perhaps due to compromised kidney function, or bladder problems...drinking small amounts more often can sometimes fix that problem.
Not drinking enough:
increases your risk of urinary tract infections and kidney problems.
Drinking too much fluid:
can cause problems with kidney function, electrolyte and water balance
Word from the Wise:
There are people that will say, "drink when you are thirsty, and you will be fine" - this is not necessarily good advice - by the time you notice you are thirsty, you are already a little dehydrated. Better advice is to maintain your hydration.