Does my one year old have developmental delays?

My daughter will turn 1-year old next week. She rolled over at 4 months, could sit up unsupported at 5-1/2 months and started scooting at 9 months. However, she still rolls over only one way and does not pull up to stand yet. She just learned how to bring herself to sitting up from lying down and still cannot lie down from sitting position by herself. Her pediatrician is not concerned about her not crawling, but she is concerned that she has trouble bringing herself to sitting and lying down and has referred us to a development specialist. This has freaked me out. I thought my daughter was just a late bloomer. But now I'm really scared she may have some problem. I can't wait to see the development specialist, but it's a few days for the appointment and I'm freaking out! Has anyone else had similar experience? Am I just being paranoid or is this really a cause for concern?