Marriage in early 20s

I need opinions or ways how to talk to my parents, anything 🤷🏼‍♀️

I have been dating my man for 4 years and the relationship is serious. We want to get engaged and get married eventually. We have been talking about it for awhile now but my parents... Ugh I know I’m their child and they are worried about me but they think I’m going to find someone else, so I shouldn’t be settling down for this one. Um hello... we have been together for 4 years. I think it’s time to get on board... He is in the army, he is currently stationed in Korea and we don’t want to do long distance relationship anymore. He is coming back home at the beginning of next year and we want to move in together. How am I supposed to talk to my parents? Should I just wait for him to propose and then they will understand it’s serious or what? They keep saying “We are older than you, I know how life turns out. Listen to us....”

I don’t want to break my family nor I want to stay away from my parents but is it really their decision who I’m going to marry? Who I’m going to live with? I need opinions what to tell them. How to approach them. I need support in this one... 🙃