She didn't need to. The thing that forced her to give those details was that she came back with fish, not that she entered the colony at all. And this appears to be the first time she's got a fishing partner.
That is what i thought as well, but it is kind of hard to believe you can re-enter colonies at will without identification at all.
my best guess is she's faking having a partner and sneaking out to do one man fishing, and hops stations when they are about to decouple from their connection period, we are not made privy to the security of other stations...for all we know this is the first paper trail station she's been on since by everything we've heard, the various groups have widely divergent cultures and value
Maybe Dione will weigh in to this stuff next chapter, how she exactly lived her life until she met Terra. I still like to believe that she was trained under her Mother in secret until Gendo were about to force marry Dione. But Dione does say in this chapter "that female Pilots are allowed in other clans". Either she also experienced that or she said it in context to what Terra was saying about female Pilots. You could interpret it either way in my opinion. And since Gendo looks for her in secret, she might escape each time they get near her, as you said. Wonder why all that fuss is about one escaped girl, though. Maybe she is someone of important descent or Gendou is simply afraid of their colony secrets leaking or something.
But i still find it hard to believe that she did so many flight hours while ship-jumping, especially since we don't exactly know how the identification process works when re-entering other colonies. I assume her flight experience is real, and she did not lie about it when showing Terra some kind of hologram (evidence) about it in chapter 2, so it makes more sense to me that she trained to fly a Twister under her mother (in secret), as she said.
I really like the world-building so far, makes you speculate about various things. I just hope there will be a good balance between the story and yuri, because usually one of those things will fall short because of the other. Yuri is often best when it is also the main focus.