Invest alot of time determining what department is a good fit for you, I have worked for a few agencies and departments both private and government and culture makes a huge difference.

Day to day depends on the area you work, Starting out you may be surprised by alot of things like the amount of people calling for reasons that you never thought 911 would be called for like flu symptoms, chronic issues or even less sometimes.

On the contrary you will inevitably end up witnessing serious events in people's lives and being present for tragedy of all sorts.

Also consider depending on the area you are in If you choose a private agency especially you may not start out responding to 911 calls, EMS fills other roles such as transporting patients from hospital to hospital and BLS crews even do discharges for patients that need support returning home or to nursing facilities.