A TER search on name (Sarah) and phone number brings up this profile:

http://www.theeroticreview.com/reviews/show.asp?id=202633

Clicking on the BP ad in that profile (from January) says she's 18, and of Brazilian and German heritage.  But the BP ad you linked to from March says she's 19 (happy birthday!) and of Columbian and German heritage.  OK, so they are in the same continent, could just be a little confused on that.  

She also seems confused about her name, given the two ads you posted links to with the same pics and phone number, but different names (Angel vs. Sarah).  No TER profile under Angel with that phone number.  Also, "Angel" is 21.  Hmmmm....

So the "official" name per TER at least seems to be Sarah.  And there is one review there, from June 2012.

Whether it is the woman who opens the door is another matter

She looks really hot.  I hope she turns out to be the real deal, but the odds aren't in our favor on that.  Most likely if she is real, she will have a list of rules a mile long, be unreliable and disappear from the biz in a month or two.