Start biking once your baby sits well unsupported and holds their head steady...

https://www.a1bookmarks.win/most-experts-suggest-waiting-until-your-baby-turns-one-they-need-strong-neck

Start biking once your baby sits well unsupported and holds their head steady in a helmet, usually around age one. Choose a front seat for bonding, a rear seat for growth, or a trailer for extra stability. Keep your first rides short and fun.