Veneers at age 15? (photos)

At age 15, I believe you are too  young for a traditional veneer, which usually requires some preparation or filing of your natural, healthy tooth.  I feel a better option at your age would be cosmetic bonding, if your are able to find an experienced and skilled dentist in this procedure. This should last you for several years or longer, and can be repaired or touched up periodically at a minimal cost.   When searching for a cosmetic dentist, you should ask to see photos of his before and after treatment to make sure you like his results. Also, the dentist should be able to provide a "mock up"  which is done by placing a resin material on your tooth and shaping and curing it so that it gives you a preview of the final result.  In this way, you can be certain that you will receive the aesthetic result that you are looking for.  

it is my considered opinion that first you should be treated with Invisalign, and then, following your successful treatment, have your teeth veneered

     I think veneers at your age is a bit of overkill, as I can see you have a good looking smile.  It will take a skillful doctor to match your other front teeth but it's very doable.  As for it moving, it may not have a good bite or there's something else going on I can't see.  A thorough exam will reveal the reason for the apparent movement.

I would suggest rebonding the tooth and wait until you are older to do the veneer.  I had the same situation with my front tooth when I was 14, had bonding done until about age 28 then did two porcelain veneers so that they would match.  I have since replaced them 1 time.   Hold off as long as you can then do two veneers.