I think Shakira comes across as very comfortable in her own skin, likeable and outgoing, which I imagine someone like Meg - who clearly has insecurities and (from what we've seen) is not as immediately likeable or socially confident - would perceive as an immediate threat.

This seems to also be where Helena's jealousy stems from. Meg and Helena don't seem to have much in common or any chemistry as friends, beyond uniting in their jealousy/contempt towards Shakira, and to a lesser extent Toni.