I believe that it can be 'lost'. My son was diagnosed with it when he was three and a half. I took him to the clinic because I was looking for additional therapy. I was extremely dissapointed to learn that all they could do is diagnosed.
He did however received hour upon hour of speech therapy and OT. He received this therapy through the state's regional centers, San Jose State University and the school district. I also made sure he attended great preschools from the time he was two and a half.
At age seven, he is now in a private Catholic school. He had to test to get in. He is above grade level in reading and math and loves to socialize with the other children. He isn't as 'mature' as some of the students. He definitely isn't the popular kid in class. But he does have friends.
He is still quirky. He doesn't like jackets and cups that have words on them. He has a hard time regulating his volume of his voice. He is also very loving and has a fantastic sense of humor. I guess the doctors would say he still qualifies for the diagnosis. But, during his IEP through the school district, the Occupational Therapist pulled me aside and told me to throw away any paperwork that gave this diagnosis because it would close doors rather than open them.
So after careful thought, I have chosen to be careful where I share this information. I am always honest and adknowledge with teachers his quirks but I don't use a label. He functions quite well in his environment but I am not blind that we have more work to go.
There was a time where I wondered if he would ever learn to talk. He now speaks very well and reads above grade level with comprehension.
So the 'lost' diagnosis really begins with you. Make sure that she gets every therapy, every chance to socialize, and every opportunity to explore the world and the wonderful places in California that can enrich her life. Make sure that 'doors' are not shut in her face but open.
Take risks, without them how can she learn to operate in this world? This means that if you have the opportunity to go to Disney World or other far away places, you take them even though she might throw a fit in the airplane terminal.
As her parent, you will need to learn to think outside the box. I always feel like I am playing Survivor with him. I have to outwit, outplay, and outlast him. But some of my best parenting skills have been developed because of him. When he needed to be potty trained, he refused to go no. two in the toilet until I came up with a chart system. I drew brown clouds and everytime he went in the toilet, he colored one in. At the end, was an equal sign and a picture of a toy he wanted.
To be honest, I too, probably would have been dianosed with PDD-NOS as a child. I certainly had my quirks. Back then, this diagnosis did not exist. I am a graduate of college, am happily married for the last 17 years and have three children. When I was placed on bedrest during my last pregnancy, the parents of my fifth graders class and my bunco group got together and made dinners for us every night for four months. To me this is a testimony of how well I function in this world.
No one knows what the future may bring. My brother was 'good' at everything. He should have been very successful at 'life'. But at 36, he is still living at my parent's home and can barely hold a job. Meanwhile, if you looked at me, I should have been him. I'm not. I know that my own son will most likely succeed because he is so stubborn and that stubborness will hopefully become perservenance.
Good luck...most importantly, always ask yourself, What would you be doing with her if she did not have the diagnosis? Then, do it!