M.G.
Comparing kids is kind of pointless - none of my kids are similar and developed at different rates and hit milestones at different times.
However, if your gut is telling you something is off - write down your concerns as B suggests, and take to your pediatrician (as you have here) and go over them. List examples.
Does she go to school? Talk to people who interact with her - who have experience with other children. Get their take on things. Take that info to pediatrician.
If then you need to have her evaluated further, you have this all documented.
Waking at 3 am is not typical, but not unheard of. Mine didn't - slept through at that age. When you say talks like a 2 year old - do you mean she does not have vocabulary? Then you should be addressing this with pediatrician and perhaps speech therapy is required. Some kids need help. One of mine went to speech therapy.
We can't diagnose your child obviously - best thing to do is trust your instincts, and talk to the person who can best guide you - her pediatrician.