Is this not normal? I don't get attached to people.?

It occurred to me today that people have gone in and out of my life, and I don't feel the least bit of attachment towards any of them. My best friends have moved on, or away. I enjoyed talking to them and hanging out with them at the time, but there is a sense of relief for me when they leave. It's tiring to try and be interesting and uphold conversation. I'm a quiet, and reserved person, content to stay by myself and just float through life without worrying about tending to a relationship. Recently, a friendship that had grown over 3 years was wrecked because I just decided she wasn't worth the trouble she was causing. She didn't like my sister, she tried to put me down and make me feel inferior. A real queen bee. I don't miss her at all. I feel like it's simpler. Is it normal to just be able to end relationships with friends and feel nothing? Even my family. I'm about to leave for college, and I don't feel anything about it but relief. It just doesn't feel right. I don't feel close to anyone I've ever met. I've never had a boyfriend. Never felt the need. I'm not soulless, though. I want to meet the one and have a happy, long life with him. I just don't know how I'll be able to. I don't know what it's like to love somebody.