Is it ok to let my baby cry herself to sleep?

Yes: Children need to learn how to sooth themselves and the younger the better. If you know she does not need to be fed or changed, is not sick or in pain, then let her cry for a short period of time, i.e. 5 minutes. You can then check on her, even pick her up, but put her back in the crib awake, and leave for 10 minutes. Gradually increase the time periods, and you will be amazed how well she'll do.

Yes: I have seen no data that would support the idea that letting a newborn or young infant cry impacts anyone other than those observing it. Tired babies often cry to indicate they don't like how they feel & want you to fix it.They are not aware of sleep but do so naturally. Behaviorists have documented a 4x higher rate of prolonged sleep disturbinces in babies rocked to sleep.