??

I like my roomate's girlfriend's younger brother. I liked him before I knew he was her brother, but now that I found out he is... should I ask her if he might be interested? Even though if he's her younger brother it means he must be like 5 years younger than me...

Saduse him. Find some way to be alone with him. Then have your way with him. All little boys want to get fucked by a girl the same age or older then them.