Hope all is well.
I suggest you get the tattoo somewhere that is hidden. I think it is so wonderful that you are getting the tattoo in honor of your grandma but depending on where you work or what people might think, it is best to conceal the tattoo. People's perception of tattoos can be negative or positive so to be safe, have it done where it can be concealed. You can still celebrate your grandma and assure yourself that you will get the job. Hope this helps and have a great day.
As someone in a white collar job, in my experience the workplace and world are evolving to be more generally accepting of tattoos but it does depend on your career. As Sarah noted, those who work in visible professional presentational environments or more conservative jobs may struggle, but as an athletic trainer you're unlikely to deal with that level of scrutiny. In general, a tattoo will be less of a challenge if you are able to hide it.
The main tattoos that would be a struggle for workplaces, in my experience, are those on the face, neck, and hands. Aside from those locations, the only other thing I have seen impede people's prospects would be extremely large volume/area tattoos that are hard to hide - high color contrast full sleeves, full legs, full back, etc (things that might show through a shirt especially). Small-medium tattoos on the arms, legs, feet, ankles, back, etc are easier to hide and have not been challenges for my colleagues who have them!