We started at about 10 months so there will be a bit of a difference in size, however, Weeride great bit of kit, still using it now for commuting as Satsuma Girl is at nursery where I work. Bobs them around quite a bit when regards of how smooth you think the path is, but as they get older you can have a good conversation with them as they ask what things are. Rear mounted seat I don’t think you’d get that and they would have a view of your backside.
The only down side is it does force you ride a bit like john wayne having just got of a horse. So if you have a short top tube and are tall then it may not be a comfortable position I’ve also had to drop the saddle a bit as I can’t fit between the seat and saddle if I need to stop at traffic lights which exacerbates the first point. However these aren’t enough to put me off and I’d buy another one if I had the need for a second because the pros definitely for me outweigh the cons.
We went for a Specialized Mio its essentially made like a decent adult helmet with inmould, head retention etc. it went small enough for her head but also has a magnetic chin strap clip so you can avoid the painful catching a bit of chin in the clip.