If you look at the HSLDA legal analysis:
http://www.hslda.org/laws/default.asp?State=MO
You're exempt from the hour and subject requirements, since you're older than 16. So all you have to do is fulfill the recordkeeping requirements, basically a daily log of educational activities, a portfolio of work, and some sort of regular evaluations (yearly standardized testing would do just fine).
Or you could go an even simpler route and put together “other written, credible evidence" for your work - basically, AP / CLEP standardized tests, which you should be taking anyway for college credit.
Once you turn 18 you don't even have to worry about this.
EDIT: From your other thread it appears you've already completed more than the 16 "statutory credits" necessary for exemption from the homeschooling legal requirements, assuming of course that you can prove you completed the coursework.