PCU vs. ER

I've been working as a Cardiac PCU Nurse for 3 1/2 years, and I've been thinking about trying the ER. I've recently been offered an ER position but the shift is 3pm to 3am and I'm used to a 7am to 7pm shift. I applied for a 10am to 10pm shift, but the nurse who is working the 3pm to 3am shift now in the ER wanted the 10am to 10pm shift. So, I can take the 3pm to 3am shift in hopes to jump into an earlier shift when one open up or I can stay working as a Cardiac PCU Nurse. I like my schedule, my co-workers, and my director on PCU. Plus, I know what I'm doing there and am one of the lead nurses. I think working 7am to 7pm is good for my husband and I, but 3 days a week is 3 days a week no? I'm having a very hard time with this decision. I'll have to start from the beginning. I did always want to try ER but I am worried what the change in time will affect me. My director now said I can always come back, so I'm thinking no risk. I can always try it to see if it's for me, and if it's not I can always go back. I know it's ultimately my decision, but and input?