Wow, that photo on the right shows that you've developed some serious length in that stache!

Here's another vote for Triibeard's advice. You simply won't know what length you prefer until you try. Keep it growing and, if and when one day you think it's too long, it's a piece of cake to trim, obviously.

Personally, I think this is a great look for as it really flatters the shape of your face. Some additional length on the chin will only amplify that (in a good way).

Cheers!
Tom


Some helpful links:
Library Central of Beard Growing


Taming the Wild Mustache
Tips for eating and drinking with a big mustache

Excess on occasion is exhilarating. It prevents moderation from acquiring the deadening effect of a habit. ~ W. Somerset Maugham
A jerk with a beard is just a bearded jerk, but a bearded gentleman is awesomeness personified. ~ Triibeard