Wait until your baby holds their head up and sits independently, usually by age...

https://griffinphut760.theglensecret.com/is-riding-on-the-sidewalk-actually-safer-for-you-and-your-child

Wait until your baby holds their head up and sits independently, usually by age one. Choose front seats for closeness, rear mounts for stability, or trailers for a cozy ride. Always ensure a perfect helmet fit and keep your first rides short.