Usually that is not a problem, as the time for each developmental milestone varies widely, walking is on the average of 12month but may extend beyond this time in normal individuals, what is actually important is the general development of a child, is he doing other things he is meant to do? Did he sit , crawl ,babble, etc at the right time? I believe your child is normal if other milestones Expected of him were achieved at the right time frame.

Why are you rushing him, every baby have a different milestone,

Can your baby crawl? Sitting up?