Hi silverstar
Your ESA will stay in payment until as you say one day before you reach state pension age, you can check your state pension age;
www.gov.uk/state-pension-age In answer to your question, no you will not be without any money for 3 months, you will be sent a letter 3 months before your state pension inviting you to apply, if you have not yet already done so you need to get a gateway reference number from Gov uk, this makes life much easier when communicating with Government on line.
Gary
