I have a Scott Speedster S50 with Sora and when I first got the bike it was a perfectly adequate group set. The shifts could be a bit heavy but it was perfectly good for when I started out.
However, having upgraded to a full carbon Cube Agree GTC Race with Ultegra; the difference is night and day.
I've kept my old Scott and it will become my winter bike this year. I am looking to upgrade the group set to Tiagra though. This is mainly because I would like 10 speed instead of 9sp and also to get rid of the goddamn thumb shifters. Like someone said previously; the new Sora does not have these.
In conclusion, I would say that Sora would be perfect. If she's not happy with the braking then you can always upgrade the pads to Swissstop's.
Hope this helps
Cheers.
Liam