I highly suggest you really investigate this and think twice about it.
A former co-worker of mine, his wife "went back to school" about 15 years ago in her late 40's. She wanted to "make a difference in the lives of kids who need a chance". So she got her degree, got her teaching certificate and secured a job at a middle school where she wanted to be. It is in a tough neighborhood in an Atlanta suburb, the school is widely known as a horrible place.
After 6 months, I started hearing the stories of "these kids are the 4th generation living in government housing, living completely on welfare, etc." "These kids have never seen a family member get up and go to work." "most of these kids don't come to school two consecutive days a week".
On and on and on.
I think she made it 18 months and walked out.
Not saying every school is like that, but from what I hear, public schools, even in the best neighborhoods, aren't what me and you went to.