Hey, Premium routing is currently being gradually rolled out. Not all users can see it yet, even on Pro.
Your subscription is active and in good standing, so it’s not a plan limitation. Once the rollout reaches your account, the option will appear in the model picker automatically.
In the meantime, you can manually select specific models from the dropdown. This gives you the same result, with API pool usage at per-model rates. Premium routing basically just auto-selects a high-quality model for you.
For reference, here’s a thread where other users discuss the same thing: Premium model selector