Walking with support at 15 months of age is normal . Child should start independently walking by 18 months of age , if not its delayed walking which needs evaluation.
If the child is floppy or overly stiff, using only one side of the body,not bearing weight through legs, always better to consult your nearby pediatrician for milestone evaluation.
Next Steps
Monitor independent walking for 1-2 months more
Health Tips
Encourage walking by keeping tempting targets like toys .