Wait until your baby reaches the 9-12 month mark to start biking. They must...

https://gunnerawsh736.cavandoragh.org/is-it-safe-to-bike-with-a-baby-if-they-were-born-premature-a-guide-for-parents

Wait until your baby reaches the 9-12 month mark to start biking. They must hold their head up steadily while wearing a helmet and sit unsupported