I went right into the ER after graduating, but my hospital had a pretty good, long internship. I wouldn't do it without a really good internship, with a hospital that is used to accepting new grads into the ER.
Yes you will have people you work with stating that new grads don't belong there. Oh well. Get over it.
And yes you will feel overwhelmed, and underprepared. There are so many little things to learn, in addition to the big things. Things that were difficult for me were silly things like what patients should I go to the docs with, and which ones should I just leave in their rooms for the docs to get there when they get there. Some are obvious of course, but others...I just didn't want to "bother" the docs.
We also are supposed to begin the process of ordering labs...the docs add to what we've started, but we are supposed to know or have an idea of where the particular symptoms are pointing...should I draw blood or just a chest xray for the asthma patient? What if it's not just asthma though? Should I do a CBC & a CMP for the person with the fever, or is this one that the doc will say "flu" and not want anything done? I didn't want to look "foolish" by over-ordering, or by doing nothing! Get over the fear of "looking foolish", it eats up way too much energy!
I used to cry in the car on the way home, because of the way my preceptor yelled at me, pushed me HARD, told me how many things I'd done wrong, expected so much of me. Sometimes even now, almost a year after I started, I get that teary eyed feeling after work because I'm TIRED of feeling stupid and new!
If you don't mind feeling stupid & inadequate, and you're willing to put yourself through about 6 months of hell, emotionally that is, and another 6 months of ego-bruising loss of self-confidence...then go for it. It's tough, and a HUGE learning curve because you have so much other stuff to learn in addition to ER protocols...but if you go in with the attitude of "I can put up with anything for 6 months" you'll be okay.