I followed baby's cues instead of following number of months! My doc gave the approval at 5 months+ but I waited as my baby didn't show interest in food and I didn't want to force.
- when baby could sit upright with minimal support
- when baby show interest in food
- when baby could put things into mouth
- when baby had good head control and neck support (not tilting or wobbling).
This was at about 6 months 2 weeks for my baby! Do a lot a lot of tummy and floor time if baby hasn't hit the milestones :)