Blue Rose was definitely not the origin of the AGE system. (Pretty sure Roger was right, it was Dragon Age.) Blue Rose 1st edition was an early (if not the original) iteration of what became True20, which was a stripped down version of OGL d20 that eliminated all dice but the 20-sider.
Bother, I was going to fix that in the notes but evidently failed to do so.
Blue Rose (2005) was the origin of the True20 system (which is d20-based, but your stats are +1 or -1 rather than 12 or 8).
I think Dragon AGE’s system is a descendent of True20 – or “inspired by” perhaps. In common with all the AGE games, stats are +1 or -1 and you roll 3d6; and it’s the first game with that specific mechanism. (Then Fantasy AGE was the genericisation of that.)
To confuse matters, Blue Rose (2015) uses the Fantasy AGE system.
To confuse matters further, The Expanse RPG is officially a derivative of Modern AGE, though it changes a lot of things.
IMHO Dragon Age does owe quite a bit to True20, and in other ways not at all. In AGE there is a probability that if you succeed then you rolled high on the Stunt die in order to succeed, so you tend to get more stunt points. Note that this also means it’s less likely that you will get a small number of Stunt points…
Fantasy Age is currently in playtest for a substantially adjusted version, much has been learnt… much from Modern AGE .
Anecdotally, while you technically didn’t need any stunt points to succeed on any given roll, you needed them to do well in combat overall and they were too unpredictable.