Most people get butterflies in their stomach when they think of attending the police academy. Well you should, its no walk in the park. You will be tried mentally, physically, emotionally, and intellectually. Most departments will require you to.
They are human, imperfect. But like you, they also have a family & a job. Their job is as stressful, or more than, that of a doctor. The difference is that they have a gun, & their lives on the line, not counting whoever is in danger!