Help on Correcting Code - Userage Permission

[Exitilus]

I'm trying to correct the code with the following Plugin:

https://vborg.vbsupport.ru/showthread.php?t=93138
Registration Denied if Under 18

The issue is even if you are 18 Today, you have to wait till the end of the month before this plugin will let you register.

So basically you have to be 18 + the remainder of days in the month.

I'm not yet at the expertise needed to fix this, but I believe I've located the part of the code that needs fixing:

PHP Code:

if ((($current['year'] - $vbulletin->GPC['year']) <  $vbulletin->options['minjoinage']) OR ((($current['year'] - $vbulletin->GPC['year']) == $vbulletin->options['minjoinage']) AND ($vbulletin->GPC['month'] <= $current['month']))) 


Just trying to figure out how to correctly set it up so it doesn't do what I stated above. I've tried a few variables but so far no luck....

Some help would be greatly appreciated