you can skip years, as long as you don't take it 4 times and you are still considered in your first four years (you haven't graduated) "Example 2. Wilbert was eligible for the American opportunity
credit for 2012, 2013, 2014, and 2016. His parents
claimed the American opportunity credit for Wilbert
on their tax returns for 2012, 2013, and 2014. No one
claimed an American opportunity credit or Hope scholarship
credit for Wilbert for any other tax year. The American
opportunity credit and Hope scholarship credit have been
claimed for Wilbert for only 3 tax years before 2016.
Therefore, Wilbert meets the second requirement to be eligible
for the American opportunity credit."
