R.Y.
My daughter was also a pretty late walker- 17.5 months! From 15 months she was standing and cruising and crawling very fast but it just took her a long time. I was told by several people that don't call early intervention until 17.5 months because they do services if the child isn't walking by 18 months. I was about to call and my daughter suddenly got it and went from first steps to walking well in under a month. But get her a push toy she can walk holding onto for now so she can practice (this was recommended to me by 2 physical therapists).