Hello everyone! My cousin is a tattoo artist. She asked me to help her translate a phrase into Latin, knowing that I’m interested in classics. Indeed I am, but I’m definitely not at Advanced level, especially in Latin. I tried to translate it, but I’m not quite sure if my translation’s ok.
The phrase is: “Iron is what has changed me.”
I guess, the person is a bodybuilder. Thus, iron in this context, I believe, is what they call weights they use in the gym. But I don’t know how this can be taken in consideration while translating it into Latin, so my translation is the following: “Ferrum est quod me mutavit.”
Is it at least correct grammatically? Are words used in the right context?
I totally appreciate any help and advice, but please keep in mind this will remain on the person’s skin forever. 
Thank you!