Wait until your child turns one and sits up unsupported. Confirm they hold...

https://future-wiki.win/index.php/Can_I_Use_a_Child_Bike_Seat_on_a_Mountain_Bike%3F

Wait until your child turns one and sits up unsupported. Confirm they hold their head steady while wearing a helmet. Choose trailers for stability, front seats for bonding, or rear mounts for toddlers. Keep rides short and always wear helmets!