you'll be next

While at a wedding on Saturday I got a bit teary when the Bride was leaving, and one of my friends said to me (in an effort to console me) "Don't worry, you'll be next!".
The comment made me wonder two things:
1. Why did she automatically assume that I was crying because I'm single? I was actually a bit teary because I was a little drunk and I'm going to miss my friend.2. Why do people always say "you'll be next" even though the actual statistical likelihood of me getting married is next to none! There are many other people who have already been with their boyfriends for years, and I haven't had a decent date for 18 months or more, so really I'm not going to be next.

I guess the comment did make me stop crying pretty quick because I was just kind of shocked by it, so it achieved what my friend meant it to achieve. But it has also been playing on my mind because I'm wondering why she would just blatantly lie and who exactly she thinks I'm going to marry, especially since she confirmed that the guy I've had a crush on at work likes someone else at work and that they've been emailing non-stop, blah, blah, blah! So just who am I meant to be marrying?