Growing up

So today I’m laying in bed, 6 days away from signing my first ever lease with my boyfriend. We’re both 20 years old and have been together for 5 years. I currently go to school full time and work part time. My bf works 40+ hours a week. We decided we wanted to move in with each other and when I told my grandparents (who I currently live with) they told me they felt like it’s a bad idea.. I could be living with them for free while I go to school. Then I told my mom and dad who live in a different state because my dads in the military and they move a lot. My mom said it makes her sick to her stomach that I’ll be living with someone I’m not married to and paying money when I could live for free. So I’m sitting here feeling excited, feel nervous, and also guilty. Is it wrong for me to want to live on my own at 20 years old? Is it wrong I want to live with my boyfriend of 5 years? It’s like they want me to stay home forever.. idk what to do. Please someone reach out and help 😞 my goal was to feel good about this, not like I’m making a mistake. Btw my income is $1,400 and my bf asked I pay $300 towards rent. College is about $2,000 / semester.