Change date to age

Hi. I have a very small project for you. One custumer needs to change one thing on a site. When user registers it asks for date of birth(day, month, year). These need to be replaced by a simple field where they can enter age. Files needed to change: register form, profile page(where date is shown), edit profile info(where to edit the age) and a search form(currently searches by age but from the date). Payment: 10$ Need it right now, so probabily first to bid is winner. Good luck!