[1.19.2] Make baby zombie have a distinct model from adult versions

I recently created copy paste zombie mob from scratch with a Blockbench model, and the problem I encounter is that the baby version shares the same model with the adult but with baby's hitbox. How should I overcome this, I prefer to turn off baby zombies entirely for this mob, if that is impossible then how can I implement the correct model for baby versions? do I need to make one in Blockbench first?