I'll say it again--Jean's shields have yet to be broken. Her TK is strong enough to hold up something as large as Avalon, blow off Arishem's hand and knock opponents hundreds of miles. Even after a resulting shockwave felt throughout the universe destroyed Shiar spacecraft, her shield remained in tact.
Her TP has global range. She's gotten the best telepathically of opponents who were immune to TP (including those with magical immunity). She's managed to drag people to the astral plane against their will (while they are shielded from TP).
And as far as the infamous speedblitz, her shield held while both Supes and Flash were banging away. While this isn't canon, nothing in a canon source has proven contradictory to the strength of her shields.