Not that specifically, but here's what a judge will say.
The child does not stop eating or doing softball or piano lessons while you're looking to decide your next move in life. If you were still together with the child's mother, it would be a joint decision on whether or not she would pick up the slack in the family, but she (and your child) are not required to just agree to lower child support just because you reached your retirement opportunity and want to go find yourself rather than stick around for another few years at the job. Now if retirement were forced upon 43 year olds in your career, that would be another question altogether... but retirement is NOT mandatory. You are doing it to better yourself, and if you choose to do that, it does not get rid of your other obligations... rent/mortgage, food, wahtever... AND CHILD SUPPORT... and if your current wife (or parents, or a VA entitlement or whatever) is willing to help foot the bill for you to stop working for a while and go to school... then fine... but that means THEY will be paying the child support... which needs to be your FIRST obligation.
They won't require you to get a job... but they will require you to continue to pay, and they probably won't reduce your child support payments just ecause your income is lower at that point.
The wonderful thing about a high risk career (military, firefighter, law enforcement) is that you build an entitlement to retirement faster than with other careers. But what that means is that it's an OPTION to retire and re-invent yourself once you're in your forties. It is NOT a REQUIREMENT to do so. And your ex wife and child are not going to be forced to cut back so that you can exercise your option on that. It's not THIER option, it's YOURs. THey still eat, need new clothes every season, need haircuts & extra bedrooms and ... well, all the things that go along with having a kid.
You are already planning on cutting back. Already planning on having your current wife pick up the slack. Just plan on her also picking up the slack on whatever support payments will be due, until your career change is complete and you're able to make up the difference in income with a post-retirement second career.
The good news is that lots of people have done it, and come out with a MUCH better life at the end withotu ever having to cut off their exes and children at all. The retirement that you're entitled to can help pay for that and ease your way into a really enjoyable retirement career.