I have wanted to reply to this, but I just did not know how to reply without coming across as if I am not dismissing your advice so I wanted to take some time to collect my thoughts.
As far as OP, I think your advice is well written, but I also think you're being a bit ignorant to say that just because she is 23 and a college drop out means she does not know anything, and that just because her parents have more life experience, not to mention a marriage that has been going on for at least 20 years, means ultimately that they are some holy grail.
Here is why I say this. I was 18, barely graduated HS (but came out with a Cosmetology license as well), and met my 24 y/o SO. He was very well put together, almost the complete opposite of what OP describes her SO as, already had a business for years that was and still is today successful, and yet my parents still persisted with their dislike. Why? Because they looked into his history, which they have no idea of, and based everything off of that. Even today they dislike him. What they failed to see was his life long struggle and that he has been on his own since 16. They failed to listen to anything I had to say, because I had only known my SO for six months when I decided to move in with him and "they had more life experience and were married for 20 years." So, what the fuck did I know?
Over the last five years with my SO my life has 10000% changed. Everything. If I would have listened to these people who claimed to have more life experience and relationship experience then I did or my SO did then I wouldn't be farther along in life then they are at 22. I would not have more financial freedom then them and most 40 year olds even wish they had, I would not have the credit I have, I would not have been anywhere near meeting my potential as I am, I would not have gotten as far within my athletic career, and quite frankly I would not be with the only man I have met that can actually put me in my place then keep me there. My SO had and has more life experience then both of them, combined, and I saw that. I trusted his words because I saw his actions, I saw the type of life he offered. I don't know if I lucked out by being "smarter" then a typical 18 year old, but I knew what was best for me. I also realized that my parents are average, they think down here while I think up here. This is not to say they were bad parents or that they are not good people, they are and I love them for what they are, but just because you may have x amount of time involved in something does not mean you actually know what is best.