So I want to make a basic calculator for a website. The goal of this calculator is to tell you how many days old you are. The user inputs a day, month, and a year, and the calculator tells the user how old they are. I want to use generic form drop down menus. I also would like to know what calculation it would have to be. If user just put their age in, they could be +/- 364 days of it, so what should I use? Help would be greatly appreciated!