At 18, I would wait a while. Give the relationship time before making such a huge commitment.

Regarding visiting/living in South Africa: I've lived in Cape Town my whole life. Had my car broken into a few times and house once. There is crime but it depends where you live as well. Definitely more in Gauteng and surrounding regions. It is also a matter of not being stupid with regards to walking around late at night in the wrong areas and an awareness e.g. not leaving things in your car, keeping your handbag closed. Yes, the crime can be more violent but it depends where you are. South Africa is a beautiful country with amazing people of all races. There is so much life regardless of the crime and racism. It is not perfect but there is so much to see, experience and learn. Do not let negative views stop you from visiting.

Regarding jobs in South Africa: it depends what you do and are willing to do. The unemployment rate is high but if you are entrepreneurial you can make your way. Not sure about requirements for foreign job seekers but I do meet many foreigners who do work here. Best to often first find a job through a company before making your way here for work.