Lexi is 5, and has about 1/2 an inch before outgrowing her marathon. The main problem with this, is she is very attached to her Marathon. it has been her seat since she was 15 months old. She doesn't like for me to let my nephew ride in it, and really hates when she has to ride in another seat. We have talked about how she is almost too big, and soon we will get her a booster. She does well in a booster, and has ridden in one a few times. But, she doesnt like any of the boosters I have showed her. Any tips for helping her adjust? I am hoping to get the new seat in the car soon so she can chooe which one for a while until she outgrows the Marathon. I will also be getting a different cover for the marathon before anyone else uses it and have considered making her a small quilt with some of the pieces from her marathon cover (Mariposa) to use in the car (she is a blankie fan as well). Also, anyone have any ideas of boosters that are yellow with butterflies?