Thanks for your query.
I will try my best to provide you with best possible professional recommendations to your questions.
I advice you not worry, your baby is fine. lower central incisor erupt by 6 -10 months and followed by upper by 10 - 12 months.
By 12 month baby will take few steps.
But if you have still doubt of any kind, i advice you to see the pediatrician
and get your baby examined.
Yet again, I do hope that you have found something helpful and I will be glad to answer any further query.