At that size she should be in a smaller container. When a seedling first goes into dirt the plant spends most all it's energy growing roots to support the plant. Not until the root system grows to the pot sidewalls will it start to show much growth above ground. You should transplant her into something smaller, nothing larger than a one-gallon pot. The roots will reach the pot sides much quicker and start to green up faster. Leave her in the small pot until the plant is twice as tall as the pot is wide. Experience has shown me that frequent transplanting is required if you want the plant to be as bushy as possible in the shortest amount of time.
Good luck, BigSteve.