R.W.
Most milestones you just CAN'T compare to others because babies vary SO much. My son crawled at 9 months and my daughter at almost 11. They both walked at 14 and are completely active, smart, healthy kids. Some kids are more motivated than others to learn physical milestones, and other kids excel more at academic milestones. Try not to compare and definitely don't worry!! In fact, ENJOY her not being mobile for as long as you can! :)