Alice can use her Readied Action as a Reaction if, and only if, the Incapacitation is removed before the start of her turn
The rules for the Ready Action specifically stipulate that it allows the user to use their Reaction "before the start of their next turn":
Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn, which lets you act using your reaction before the start of your next turn.
—Ready, Player's Handbook, pg. 193
So if between being paralyzed and the start of their turn, the paralysis is removed, then they would be permitted to carry out their Readied Action.
The only major exception is if you were holding Concentration on a readied spell, since incapacitation breaks concentration:
Normal activity, such as moving and attacking, doesn't interfere with concentration. The following factors can break concentration:
- Being incapacitated or killed. You lose concentration on a spell if you are incapacitated or if you die.
—Concentration, Player's Handbook, pg. 203
So because the Ready Action requires you to maintain concentration if you are using your Ready Action to cast a spell, you would lose the spell, and therefore your Readied Action, from being paralyzed.