Should I pledge a Sorority even though I'll be the only pledge and my boyfriend is against it?

My boyfriend is in a fraternity and by hanging out there I've meet many different sororities and have many friends in them. I really want to join one of them but my boyfriend is against it, i have a busy schedule this semester, I was told I'd probably be the only pledge, and I am older than most people who pledge. I really like these girls but I'm still confused as what to do.