Well, I had one when I was 23 or 24. My ob-gyn felt it during an exam. It hurt like hell a few weeks later, my parents took me to the ER, where they promptly misdiagnosed an ectopic pregnancy. That was a false positive from a UTI. They saw the cyst and let it be. It eventually went away. Of course, this was before ultra sound, or at least ultra sound for single, supposedly pregnant women!
The waiting sucks. Have you had a trans-vaginal ultra sound?