Wait until your baby sits independently and holds their head steady while...

https://www./parenting/when-can-a-baby-go-in-a-bike-seat-an-age-by-age-guide/

Wait until your baby sits independently and holds their head steady while wearing a helmet, usually by 9-12 months. Front seats offer interaction, rear mounts provide stability, and trailers allow for cozy naps. Prioritize neck strength over age always.