A dorm is not the same as a house. There is supervision at dorms, and the student is not responsible for the building. A college student in a dorm doesn't have to worry about a break in, house fire, electrical appliance malfunction, power outage, etc.
I went to college at 17. My parents didn't leave me HOME alone overnight until after freshman year of college and I had turned 18. The following year, as a sophomore, me and 2 others shared an apartment off campus. THAT is when I finally felt like I was living "independently." Dorms are a managed setting with adult oversight (RAs, campus staff).