Nick, I suggest you try to get some part time work in...it isn't like hitting a ball all day, it takes a special type. Not saying that it isn't for you, or you would be bad at it, but it isn't like getting paid to play tennis all day. Some of the stuff you have to deal with are.
1. Small, misbehaved kids, who do not listen to you, and cry for no reason.
2. Older kids who do not want to be taking lessons, and have no aspirations of getting better, and who put forth no effort, and generally just dont give a crap.
This is what pros hate, and we call it babysitting.
3. Your assortment of housewives, hit and giggle players, chronic lesson takers, blah blah blah, they are good people, but are possessed of almost 0 skill or ability, and not willing to practice to get better, so all you end up doing is dead ball drills or tapping the ball back to them in rallies/games.
4. Stubborn people who tell you straight up that they refuse to change their current stroke, they don't care if it is right or wrong, they feel comfortable and are not changing.
5. People with unorthodox/hacker strokes who have been playing that way for 30 years and can play 3.5 or 4.0 and just now decided that they want lessons.
6. The parents of tournament playing juniors.
7. 4.0 players who think they will be in the US open with just a little more practice.
8. The list goes on, and on and on.
Once in a while you get a good player to hit with, or someone who genuinely wants to learn, or good tournament playing juniors whom you can help. But in the beginning, you get stuck with all the little little kids, or the hit and giggle players, or you run drill sessions, and feed balls. Just like any other job, you gotta pay your dues doing the garbage work before you can move up to the fun stuff. And you need to have the type of personality to maintain the look that you are trying and putting forth effort, when it is obvious that your lesson really doesn't give a $#!7.
Like I said, before you dive in, try to get some part time hours, and make sure you have the right personality, because it definately isn't like you get paid to play tennis all day.
You either die a hero or live long enough to see yourself become the villain.