I am a freshman in high school and this guy that I like a lot is a senior (we are 3 yrs apart). The thing is, his sister is one of my best friends, but whenever I hang out with this guy, he always seems to be flirting with me. We have known each other for 15 years, my whole life, and I am constantly flirting with him as well. He has never had a girlfriend, so I don’t even know if he’s trying to flirt with me. Another problem is that he is going to be going off to college soon. What do I do? Should I tell his sister about it? Help!