The hardest part is listening to it.  Consider perhaps turning off the monitor, and going into another area of the house during the time you will be letting her CIO.  I have to do this, or I break down and go in every time.  They will normally stop crying pretty quickly.  My son still cries out in his sleep every once in a while now, but I haven't gone into his room in a week now.  Good luck.  It will get easier, but you have to stick with it.

Yes.  My son was born 12/17 so right around the same age as your daughter.  He's been waking up a lot at night due to teething pains.  So, at first, I was sympathetic and got up with him when he awoke.  But then it got to the point where he was waking even without the teething pains.  So, I have done this a couple of times.  I would say that the first time it took the longest.  Probably 4 days of some serious crying before he finally slept.  Now, it probably takes about 20 minutes, when he does cry. 

I can certainly sympathize with you. I have been dealing with this as well. My daughter is now 18 months and I started the CIO method starting about a month or so ago. It was definitely tough at first. You sit there hearing them and feeling like a terrible mother for not comforting them, but it was the only way I found that worked. She would wake and I would immediately go in and hold her just so we could all get some sleep, but after a while that gets so exhausting on you. I finaly gave in and started one night letting her cry it out. I would let her go about 10 minutes and then go in and lay her back down and tell her to go to sleep and that I loved her and walked out. She would get upset and cry more...I would then wait an additional 5 minutes and do it all over again. The longest I have let her cry is 20 minutes. The way that I know she is really okay is because she will pause in between her cries as if to wait a minute to see if me or daddy will go into her room. When she realizes that isn't happening she will start agin and so on. Eventually, she will fall asleep.

I won't lie...it is very hard to do. Takes a lot of patience and tough love. In my own experience it has been worth it. It took about 4 days of this until she was able to get herself back to sleep. But remember this...it only takes one day to break all the owrk that you put into it and I have personally learned this as well when Sienna ended up with a nasty bug and I would sooth her back to sleep at night. Then I had to start all over again. I just can't not comfort her when she is ill.

Anyway...good luck and let us know how it goes :)