I have a Bell Bike Trailer, It has a five point safety harness, and she can hold her head up perfect. My question is is it safe for her to use it yet, and what should i do about a helmet? The smallest I have seen is 3+ years, do they make them smaller? Where can I get one if I need it? All Answers appreciated! THANKS! The back of bike carrier seats are for 12 months and up, but I cant even find a helmet that small, the 3+ is HUGE!