I thought maybe it was just because I re-installed the Radian more upright, BUT- I measured her today in the house and it is 15.25"! And she's really close to the top slots of the Radian now- maybe 1" left. I tried her in a MA just for fun in Target last week and she was over the top slots. Her legs grew, too. I am debating whether to let her outgrow the Radian and then see if she is ready for a booster before I get a Regent (again) Perhaps we can get to 5.5 yrs with an inch of torso growth? She is 4.5 now.