In my opinion you should get an evaluation from ECI and see what they say. (The evaluation is free) It may be nothing, and if it is they will tell you she is fine and you will have piece of mind. If there IS a concern, they set up a plan and have the therapist(s) come to your home.
It is MUCH better to catch any kind of delay (mental is not the only kind) early.
ECI billing is based on sliding scale. The first 6 months are completely free if you agree to let them bill your insurance, no matter what your insurance pays. After that, it's a sliding scale based on your income with the highest level at $150 a month. Believe me, that's cheap for any kind of therapy.
I wish I had contacted ECI with my first son. He had poor upper body strength, but I just thought he would "catch up" if I kept him physically active in gym, etc. He didn't catch up and we had to start therapy at 4 to increase his upper body strength to improve his fine motor skills (it's all related). At 5 he is still behind, but not as much. I firmly believe if my doctor had taken a proactive approach early like yours that my son would be further along than he is. It's hard to know what is "normal" when you are a first time mom.
We just had our 2nd son evaluated through ECI for a speech delay. I have been very pleased with them. Good Luck!!