For everyone who wondered, the current shields on NTN are:

Dark Pink ---- NEW ARRIVALS and those who have been here for 3 days or less.

The '1' shield (pink) --- someone who's been here 1 year, but less than 5 years.

The pale blue '5' shield ---- someone between 5 and 10 years (like me).

The yellow '10' shield ---- those who have been here since the early days.

The green one ---- those who currently possess Premium Membership.

in addition, we have:

The gold one ---- those who are verified as being genuine, and who are "valued members of the community".

The last one is the most difficult to get. The first four just take time, and the fifth (Premium Membership) can be bought at any time by any member. All five are automatic. As soon as anyone qualifies, they get the shield immediately.

The 6th and last one (gold shield) is a bit more difficult, which is why so few people earn it. And note I say 'earn'. It's the only one that's not automatic.