Hi there. Well, kids do absolutely develop at their own rates. Often a less physical child will be more verbal and a more physical child will be less verbal as things develop early on.
Good questions, if your child is pulling up, crawling,etc. Did your child reach any other milestones on time such as rolling over?
One thing to consider is that your little one may have low muscle tone. This is not uncommon. Often a physical therapist will work with a young child to strengthen their muscles.
You should be in consult with your doctor/pediatrician about this. If there are any other indicators that the child is developing too slowly, they can refer you to an early intervention program in your state. This would include an evaluation and services if they are needed. Sometimes just a little extra help in the begining is all a child needs. (such as the physical therapy for low tone). And if it is something like dyspraxia--- working on it early can really make a HUGE difference.
My own son walked early but has mild dyspraxia. This is motor planning and part of the sensory system. he did walk early but he skipped crawling entirely. Crawling is harder than walking believe it or not in terms of coordination needed. Anyway, we worked on his motor planning/dyspraxia and you wouldn't be able to tell now that he was delayed in his motor development.
good luck
She is still young and many dont walk at this age , is she sitting rolling , does she seem okay in other aspects ?Sometimes they crawl for a while then pull themselves up on a chair .