Yes, what you said makes sense, so I have to warn you strongly: Don't say she's shy in front of her!!!!!!!!
First of all, you don't need to explain or excuse her personality to other people. It's none of their business what type of personality she has, and anyway they can see and judge her for themselves. And you ARE conditioning her by saying those things in her presence. You are labeling her and creating a self image that is not a particularly positive one. Being shy is a burden. Instead you should comment any time she does anything brave or social, and bolster that side of her personality.
Being shy SUCKS. I was especially shy in my teens, and would go for hours in a group of people not saying one word, agonizing over trying to think of something to say, and wondering how everyone else could just so casually talk. But over the years I overcame my shyness, and if you talked to me today you would never think I'd once been that way. So you really want to try to help her to not be shy.
To that end: Don't ever call her shy again in front of her. DO PUSH her to go outside of her comfort zone, in small steps. Shy people need to face what they fear.
As a reformed shy person, I can assure you that completely reversing shyness is possible. Help your daughter to do it.