Caylen's Evaluation

Well, today we were supposed to have Caylen evaluated by Children 1st but our appointment was canceled due to the evaluator's child being sick. We rescheduled for Monday at 1. So, I figured I would take this time, which would have been during her appointment to talk about why she is being evaluated and to get all that stuff out. Caylen is 15 months, but will be 16 on the 16th of this month. She is still not walking, and we are getting her checked out. Her language and everything else seems to be great at times, but she is so inconsistent that we are not sure if we need to be worried or not. She calls everyone 'dada' and has just recently been referring to me as 'mumum.' She has said a million words once, but she only says 2 to 4 consistently. She will say new words every day but she doesn't repeat them often. Or, she will say a new word and it won't show up again for a month or more. Is this normal? I don't think she has a specific disability such as autism or CP at all, but I wonder if she is a little delayed, and why? She has always been a 'high needs' baby but I don't know if that has anything to do with it. I know there is a lot going on in her head, I can tell, and she is very able to do things fine motor wise and most gross motor abilities, but I am wondering if there is perhaps a processing problem somewhere, if anything. Maybe that is why she is easily frustrated as well. I am easily frustrated too, so maybe she just gets it from me, as well as stubborn, so maybe she just hasn't made her mind up to walk yet. I am also quiet and 90% of what goes on in my head stays there, but I don't want to assume she is the same way. It is just really hard to come to the realization that there could be something wrong with your child; all those dreams and hopes you had for this child when you were pregnant might all be completely different from what you had imagined. Like I said though, I don't think it is anything serious or even moderate, but if she even has a mild disability I want to know about it as early as I can, so I can begin to help her! I ask that you please pray for us during this difficult time, as it might be a long process before we know anything.