my parents asking me stupid questions

I'm 18 years old and I'm in my first year of college and still live at home. I've been dating my boyfriend for 8 months now. My dad came in my room this morning and asked if we were getting serious and getting engaged ? I said no I'm only 18! And I snapped at my dad because this is the like the third time he's asked me since I've been dating my boyfriend. I'm guessing my parents don't like my boyfriend too much. My mom and dad started yelling at me saying how that's not a stupid question to ask but it is because I'm only 18 and I feel it's them just trying to tear me down. My parents are saying they're mad because they know we're having sex and they're saying that means he doesn't respect me or them because he's having sex with me. And now my parents are mad and basically saying they're concerned I'm dating my boyfriend because of that. And I guess they don't like him because he doesn't fit into what they want. They just want me to have a rich tall guy. My boyfriend treats me so well and I love him so much and my parents see that so I don't know why they feel like this. Do I stop dating someone because of my parents opinion or what do I tell them to get them to back off ?