Wait until your child turns one. They must hold their head up in a helmet and...

https://wiki-book.win/index.php/How_Do_I_Explain_Bike_Seat_Rules_to_a_Stubborn_Toddler%3F

Wait until your child turns one. They must hold their head up in a helmet and sit independently to handle road vibrations. Front seats suit smaller toddlers, while rear racks fit growing kids. Trailers offer the best stability for beginners