To me the analogy of the ladder that Michael Tae Sweeney describes here is a good one.
Although editing is editing*, more often than not people don't want to take a risk on giving someone a job doing something they haven't done before:
"She might have cut comedy, but has she cut comedy with animals before?"
So you really want to decide which bottom rung, of which ladder, do you want to start off on, before you invest all that time and effort in climbing it.
But how do you do that?
How do you get a taste for what you might like to edit the most; documentary, commercials, music videos, scripted TV, features etc.
Which ladder do you choose?
*OK that's a little broad strokes. Yes, of course there are different aspects to the craft in different domains but the innate instincts are the same; rhythm, pace, story, emotion etc.
It's your choice
Personally, I remember years ago hearing an assistant editor on one of the Spiderman franchise movies describe arriving at 8am and leaving at midnight every day for well over a year and I thought; that's incompatible with everything else in my life!
I'm not saying all feature assisting is like that, but if the goal is to assist and work your way up to the 'big movies' and that's what it requires?
Well, I have other things that I care about.