dude.
It prob also doesnt help that I have 3 roomates who were in an out the whole time. <--
I hate to be captain obvious here but this kills a "romantic moment" and adds a lot of distractions and anxiety for a girl. She doesn't you know you that well and doesn't know these guys? No wonder she was cold, she was nervous and massively uncomfortable.
Making a big deal with age gap will kill your ability to make this interaction solid. I'm 28 and have been dating girls between 19 and 41 years old, age doesn't f'ing matter.
Also, forgot all this shit about DHV, just be a fun sociable guy that is cool to be around. She is not in the age group that cares about anything else.
Lastly,
"She seems like a really good girl so I didn't want to push anything more or push her to come upstairs to my room. "
Man oh man, you never "push" a girl into your room, you have an excuse to bring her into it, whether it's music, pictures, homemade movie, etc. "Hey come check out my ___" and lead her to your room.
