It's hard to for me to say. It may get root bound if you leave it, or it may just stunt flowering all together, or the plant will just slowly die off, or it maybe it will be just fine, but remeber, smaller room to grow=smaller buds, which=smaller yeilds.

If you're going to leave it in that container, I suggest switching to 12/12 now to force flowering. It will stretch biug time for the first 2-3 weeks of flowering, and in that time, your plants height can double. By the time flowering is done, it can be tripled. It all depends on the strain. Indicas grow shorter than Sativas, so if your plant is Indica dominant, then your plants height, at 14inches, should only double. If it's a Sativa dominant, it can easily double, and even triple.

Good luck.