can I set-up an email reminder to the sender 10 days before his/her event

Actually we do not have such option as of yet.

However, you might create your event form with a calendar included, then integrate it with a 3rd party mail service we got available so far. You have to have a list already. I think Constant Contact offer this service, but not fully sure.

Other solution would be to create the form with them and set it up, rather than using a JotForm and an integration with the service.