Keeping track of an eating schedule

Babies love to eat and at such random times too. One way that helps me stay on track of when she needs to eat is by setting my watch to start counting as soon as she is finished eating. She generally eats about every two to three hours, so when I check my watch and its close to being time for her to eat, I know that that's why she's crying.  A lot of times I am confused on why she is crying, but this helps a little to narrow down her hungry cries. She is only two months old now but I'm sure her schedule will change as soon as i get used to this one.