Always possible. It's highly unlikely her child was buried at this cemetery, since she wanted to remain unidentified.
II ask myself, "if I wanted to kill myself in a place but remain unidentified" - there are two things about that. One is why you'd care about remaining unidentified. If our Doe was pretty isolated (no close family, maybe few friends), then why go through all this trouble? You could just kill yourself in your home, you may get a death notice in the newspaper and it may not even mention that it was suicide. I'm not thinking that Doe necessarily had a big family, but I think there is someone she wanted to hide this from, someone who also wouldn't necessarily be concerned her if she said she was "moving" but never wrote/called/emailed - maybe friends from church, cousins that she wasn't very close to, something like that.
The other is why here. This cemetery is a mile off the Beltway, the street it is on looks pretty busy, it's across the street from Northern Virginia Community College @ Annandale, it's near parks, it's something you'd pass on the way to shopping centers and George Mason University. It doesn't seem like something a "drifter" would find (I'm hard pressed to think of any cemeteries that you'd just stumble across), but if someone was traveling in an unfamiliar area, it's something she could have seen. Maybe the local maps or yellow pages, or Mapquest which I think was online at the time, would have listed this, and unlike a lot of cemeteries this one (I believe) was easily accessible via public transit. Picking a quiet part of the cemetery (so she would not be found/interrupted) makes sense, the history of the cemetery may not have even mattered to her. It was just a quiet place for her to end her life.
So if she is one of the "missing, missing persons" as Bit of hope says - and I think this is what happened - there's a decent chance she may never be reported. If the only people in her life were her congregation, well, it's been twenty years, her best friends (in her age range at the time) may have passed on, her pastor may have retired. I think the best chance to ID would be to do something like what the Grateful Doe people did and push information about her everywhere.
