At first i have to say that everyone can get an age verification, basic or vip member, if there are the suitable conditions. Now you are 19yo and you try 1 year and a half. That means the first time you tried for that was before your 18th birthday? In this case as i know we have a small problem by the system.
You need to get a ticket and report your problem. The following link, will help you: https://support.secondlife.com/create-case/