Did they have Stephanie act older than DJ at the same age, or did Stephanie just look older?

I recently rewatched s7 and s8 for the first time in a while, and Stephanie seems so much older than DJ did in season 2-3 when she was the same age (6th - 7th grade). I don’t know if it was the writing or if candace just had more of a baby face than Jodie and looked younger. What’s your opinion?