I think most beginners realize their limits in ukemi enough that they would not resist past the point of stupidity (that is usually the realm of more senior students) and get hurt. Beginners more often fall when you look at them
, pain avoidance seems to be high on their list, as it should be.
Again, death and serious injury is rare, and usually related to stupidity, not to correct training.
Some dojos stress ukemi more and teach it early, some not so much and teach it later. How much it is stressed is usually related to how much good ukemi is needed. I think, even if it is not stressed at the dojo you choose, that learning it to the best of your ability will be good for you, not only because it is fun and challenging, but because the better you are at it, the less afraid you are, which is always nice
. Really, I doubt the risk is any greater than in other MA you have done. Some folks just talk about it more. Go visit the dojo, if you like it, try it. Aikido is really something you need to experience, talking is just not a good substitute.