Good luck, my skids are in college and we pay both cs and tuition. Sucks

What does the court order say with regard to college expenses, car, driving lessons?
Most states won't change cs within a year of it ending so if she's 17 nothing should happen there.

I wouldn't stress this too much. Like other posters have stated, you need to look at the origional CO/CS paperwork. My uncle put in his that he would pay CS until they were out of college and pay for half of their college. But he also had the option to stop CS payments to BM and put that towards college fees. He did stop the payments to BM and would give the money to his kids instead.
Now my DH got nothing in his agreement for anything other than BM paid him for the kids until they were 18 and out of high school and she was responsible for 60% of the medical bills and must carry health insurance on them and life insurance on herself with DH as the benificiary. BM did not pay for anything for my SD's other than her mandated CS payment. She wouldn't even buy them a pencil for school. But what do you expect from someone who doesn't know what being a mother really is?
A friend of mine tried to get a CS order changed when DD was 16 to include that college be split 50/50 by the parents. It never changed because the courts did not view it as a necessity for the child to live and told the DD and BM that the kid could get loans and work to pay for it.
A lot depends on the judge too. But most judges are not going to change an order so close to the end of it and as far as her insurance and driving, that is what the CS is for.

Is your SO/DH represented?

Just because it isn't in the CO doesn't mean you will win. It may be that they can attach this to uncovered expenses.

Have at the ready a list of other arguments (I'm assuming that he has joint legal custody with educational decision making rights). Typically what I will do is search leagle.com for different appeals in my state on a given topic to see how things have been argued to see what they might bring up.