Especially don't do it as a midlife career change because age discrimination is rampant in the field.
Being fired or forced to resign or retire or non-renewed as a teacher, which is a firing but you are not given a continuing contract, has very little to do with whether you are a good, bad, or indifferent teacher. It has to do with whether or not an idiotic or vengeful principal "likes you."
Not good to be a lamb to the slaughter, especially if you are thinking about this field as a retirement career:
Young teachers from across the United States have told me they no longer have the ability to properly manage classrooms, not because of lack of training, not because of lack of ability, not because of lack of desire, but because of upper administration decisions to reduce statistics on classroom referrals and in-school and out-of-school suspensions. As any classroom teacher can tell you, when the students know there will be no repercussions for their actions, there will be no change in their behavior. When there is no change in their behavior, other students will have a more difficult time learning.
Teachers are being told over and over again that their job is not to teach, but to guide students to learning on their own. While I am fully in favor of students taking control of their learning, I also remember a long list of teachers whose knowledge and experience helped me to become a better student and a better person. They encouraged me to learn on my own, and I did, but they also taught me many things. In these days when virtual learning is being force-fed to public schools by those who will financially benefit, the classroom teacher is being increasingly devalued. The concept being pushed upon us is not of a teacher teaching, but one of who babysits while the thoroughly engaged students magically learn on their own.