Hi Zoey. I've read your questions, and I'm wondering if maybe you're inexperienced with babies, or maybe you don't have a doctor for your daughter? Maybe you don't have insurance, or know how to find a doctor. Or maybe you're not sure about how to ask the doctor certain questions.
You asked about how to help a child develop mentally and physically. Of course, there are some things all mothers can do, like talking with your baby. And I don't mean all cute baby talk, but just chatting with the baby, reading books aloud to the baby, and singing little songs to the baby. And of course, babies can benefit from being taken for a walk in the stroller, or pushed on a safe baby swing. All these things help a little brain learn about the world around it.
But, when development is a concern, a parent who is not a trained therapist or doctor should not be the one to diagnose any delays or come up with a treatment plan. That's where you need a trained professional.
Your profile on here says you're from New York, New York, but that's a pretty big area. Maybe, if you don't have access to a doctor, if you told us your general area (a little more specifically than New York City) someone can help you find a free clinic or child evaluation center for early intervention.
Maybe I'm way off-base here and maybe you have an excellent doctor and are just looking for reassurance. As others have said, all babies are different. If your doctor is not worried, that's a good sign. You might talk over your worries with your doctor and ask what he or she would do.
Most of all, don't look for a diagnosis like cerebral palsy. Instead, look for results, like "how can I help my daughter gain better balance". She's just barely a year old, and there's lots of time for development.