Add option to enter Date of Birth in WP custom post type and return the actual age

Hi fellows.. We're gonna use this plugin for actors agency  [login to view URL] they will like to display the model age and be able to filter their age via WP Taxonomies. If you look at the first model example of the plugin at the top left you can see that some information is displayed in grey i.e Hair Color, Weight, Height etc.. This info is being displayed via WP CUSTOM FIELDS/META KEYS , obviously we could create a custom field for AGE and enter the model's age 24, the only problem using this method is that in 5 years from now lets say in 2018 the model will still remain 24 while in fact she'll be 29 years old, so this is not really useful or accurate method. Therefore, we will need to create a WP Taxonomy for AGE that will be related/attached to to the model's Portfolio(built-in custom post type that comes with the premium theme we're using) , and the ability to user date picker or other way to enter the model's date of birth - and obviously show in the front ONLY the model's AGE and NOT the full date of birth.. It's shouldn't be too complicated if you're savy enough with Wordpress. on the original theme I have already installed taxonomies plugin so this is not a big deal, the only thing that we really need is an option to enter the date of birth and return her actual age that will be synced with the WP clock.. Any questions feel free to ask ..