If they would be in the center - it could be too much light - (it still can be to much light looking at the rest of the plant - a bit too bunched up) - but since they are outside leaves - it most probably a natural attrition.

Thank you! I just purchased it from the Violet Barn in the fall and if anything it hasn't been getting enough light. It's been in an east facing window that's sort of covered by a tree. I've been worried about the lack of light but just noticed that it's getting ready to bloom. Very excited about that.

I agree with Irina on it being a natural aging. The leaves resemble some of the ones I remove from my plants. Once these outer leaves start to lose their chlorophyll, it is rare for them to get it back. It is better to remove the old outer leaves before they turn completely brown. You chose an appropriate time to prune them.