Also the mix looks kinda wet. Make sure it doesn't become overwatered or stay too wet. Since your seedling is still pretty small, it's less likely to recover if something happens to it

Stacy you wrote ..." I just fertilized for the first time today". Does that mean the first time to fertilize the tree ever? If so, no wonder your tree has not grown. Note: of all the possible varieties of citrus to grow from seed as a container plant, grapefruit is the worst choice,

The first time to fertilize since winter/spring is over. Its only a little over a year old. I just wanted to see if I could grow it....

If I may ask, why did you not fertilize during winter & spring?

Someone said it wasn't a good idea? Something about not needing it during the "dormant" months... I finding that that may have been wrong...

Many plants have dormant periods, citrus is not one of them. Citrus never really goes dormant.