Dynamic Dates

We have an interactive demo on our website and within the demo we have an option for the prospect to click and select if they request additional info. We created a smart campaign and a check box in Marketo so when they select this option the checkbox is checked so we know the prospect requested additional info, however, this does not let us know when they selected the RFI option.  Also, this will not allow us to know if they chose the option more than once because after they select it the check box is checked and is unable to be updated with a check if the box is already checked.

Is there a way that a date can be entered instead of a check box and to have the date updated each time they select this option to show that days date?