Thanks for the accept
The first concern I would have is if your son is charged as an adult. If this happens this case becomes very serious. Missouri allows the state to try a 17 year old as an adult in some cases.
1. A person commits the crime of statutory rape
in the first degree
if he has sexual intercourse with another person who is less than fourteen years old.
2. Statutory rape
in the first degree or an attempt to commit statutory rape
in the first degree is a felony for which the authorized term of imprisonment is life imprisonment or a term of years not less than five years, unless in the course thereof the actor inflicts serious physical injury on any person, displays a deadly weapon or dangerous instrument in a threatening manner, subjects the victim to sexual intercourse or deviate sexual intercourse with more than one person, or the victim is less than twelve years of age in which case the authorized term of imprisonment is life imprisonment or a term of years not less than ten years.
Sorry to be the bearer of bad news, but it looks like if the state prosecutes your soon as an adult, he is facing, if convicted, a 5 year sentence
I recommend you seek the help from a GOOD local attorney who specializes in criminal
Please let me know if you have more questions. I need to step away for approx 2 hours but will try and answer when I return