A woman hit my car and we made a contract for repayment but I now realize there is no consideration in the contract for her sack. Will it hold up?

Here is the contract language (names removed) I, (Woman) , Promise to pay the sum of $4,200.00 to (Me). The above stated amount will be paid with $200.00 payments every month starting with the first payment due October 15th, 2011 ending with a lump sum balance payment due March 1st, 2012. There will be no fines or fees if paid early. (Me) agrees to provide a signed letter releasing (Woman) of this debt when all payments totaling $4,200.00 have been received and cleared.