How long to wait before switching

I am a new RN (4 months) working in a hospital. I am thinking about changing to a new hospital. I work in an ICU Step down (drips/vents) and my goal is to get into an ICU. Is it too early to want to switch? I like the unit I'm on but I want higher acuity pts than they have. My goal has always been to work in ICU but as a graduate nurse with no experience, it was hard to find a job right into the ICU after graduation. Should I wait 6m? Longer? Look around now? I can get some more experience where I'm at but thinking I could get the same experience and more in an ICU. Any help would be appreciated.