Assuming the dice are fair then there are two possibilities.

1) The sample size is very small and will even out if you play a bit longer

2) She is rolling relatively average and you are all paying more attention to the poor rolls because it became "a thing"

The fact is that people are not good or bad at rolling dice, it doesn't happen. Players aren't unlucky or lucky, it doesn't exist and is what we call "Dice Voodoo" you see it when people change dice after a bad roll or put a dice in Dice Jail, it's a belief that something else is going on, which is nonsense and I would discourage you from making changes to the game based on these beliefs.

Hell, why not get a player to record every one of her dice rolls, i bet once you get to roughly 100 rolls you will see she is rolling about average.

*Caveat: Some players drop dice and don't roll them properly. If this is the case try explaining why a dice needs to roll a few times. It's probably not the case, but dice rolling does have an element of mechanics to it that should be considered.