Yes - if you start right after high school - most high school students graduate at age 17 or 18 - typical 4 year college is just that 4 years so if you go straight away to college you will most likely graduate 21 or 22. Although it is not uncommon to graduate a year later often times due to taking less classes a semester or two for a lighter load or if you change your major you might have to pick a few extra classes to graduate with that degree.
Also, many recent high school graduates are unsure what they want to do later in life and decide to take a year to work or volunteer prior to making a committment like a four year college. Some for similar reasons opt to go to a community college (2 year college) and decide after to pursue the four degree - sometimes this requires taking some extra course that maybe will not transfer from the 2 year college. Many reasonable reasons why someone would finish in what you would consider a year later.
So at 23 it is perfectly reasonable to graduate from a four year college.