High school sweethearts?

Autumn
Okay my boyfriend and I are seniors in high school and we are coming up on our two year anniversary. I've never felt this way about any other guy. Like he's helped me become a better person and to over come some of  my insecurities. Not all of them yet. But my family keeps saying that we are too young to be becoming this serious. And that I need to "play the field" and find the type of guy that I actually want. They keep saying that I only feel this way bc it's my first serious relationship. Also my bf and I are secretly engaged. I don't feel like these feeling would ever go away. 
I guess what I'm asking is can couples from high school actually make it and live happily ever after?