So I've been wondering for awhile, where are the things for timid/reluctant heroes. Things for heroes that really don't want to do this superhero buisness but do it anyway because either it's the right thing to do or because they keep getting put in the wrong place at the wrong time and the only option is to fight. Now granted I haven't seen the principles things in detail since the CRB isn't out yet, but I feel it's still worth asking.
There is the "Principle of the Everyman" that represents a reluctant hero who gets in over their head.
That said, that's about as close as you'll get with the official materials. That said, it seems that you could easily add a "Timid" personality. Offhand I'd give them a GYRO of d6/d6/d12/Defend an ally with your single [quality] die.
While there are plenty of Reluctant Heroes who will take a stand for one reason or another if they have to (and let's be perfectly honest... they usually find a reason why they have to do so... are you really reluctant when you constantly find a reason to throw yourself in harm's way when you probably have as many reasons not to?), there really aren't that many Timid heroes... at least not that many who remain relatively timid once they become a hero. Most of the time, their timid demenor comes from a lack of confidence in their abilities... something that a good mentor (and even some bad ones) often help them to overcome in fairly short order. Yes, they may start out rather timid, but as they train and understand their powers and abilities, they gain the confidence they need for a more heroic personality trait to emerge.
This being said, some of these timid heroes do still remain relatively shy in social situations, though their improved level of confidence does also help to mitigate this to a degree, as they are rarely as shy as they were before. This is clearly shown in the character of Violet Parr (don't remember if she ever decided on an actual Hero name like her parents or other Supers) from the Incredibles. One could very well say she started off as a very timid character in the first movie... even to the point of instinctively using her powers to hide from socially awkward situations as much to hide the fact that she even had powers. Over the course of the movie, she got used to the idea of using her powers for more than just hiding who she was (and yes, on a few occasions, she was pressured to use them when she felt that what she was being asked to do was beyond her capabilities). The more she used them, the more she began to see them as a gift that made her special rather than a curse that made her different... showing the growing confidence she was getting... both in her powers and her general ability to handle situations that most children her age didn't have to worry about. By the end of the first movie, she was definitely a more confident and less timid character than she was at the begining of the movie... and in the second movie, this was further demonstrated as she began to resent the actions of her parents that seemed to impact her life as well (but eventually came to see that even heroes can make mistakes and make atempts to mitigate them when they have to).
So yeah... while these types of heroes do exist... they often do not remain reluctant or timid for long... their heroic lifestyle usually brings out a level of confidence in their abilities that see these characteristics change into something more appropriate for a heroic character... or rather see other, more heroic traits rise to replace these traits. Sometimes this leads to characters that become very overconfident (even arrogant) in their abilities... but most often they find a reasonable balance given their other personality traits... depending on their experiences during these uncertain times. Simply put, Heroes with these traits often do not retain them for very long (usually an issue or two being the average... depending on how active they are in the story arc).
Many of the d6/d6/d12 personalities seem to match up with what you want.
They aren't willing to commit until things at their absolute worst, or don't realize how bad the situation is until then. I'd say one of those, or one of the d6/d6-8/d8 personalities, if they never really are willing to commit to a situation.