Age Calculator App with Javascript and responsive CSS

So, overall this was a hard one to code, mostly cause I tend to make things harder on me with trying to make the stuff more complicated than they actually are.

In the end I'm satisfied with the results, tried to cover all the bases on the inputs such as cover the date we are, and limiting the entries to the most recent possible date, for now and for the future.. so if someone went to enter this site in 5 years from now, the date should work the same as work now.

So that's it... Any suggestions?