Front Fender Crack

[Sheds1926]

Hi, I am fairly new to the hobby, I grew up around A's, and now have my own car, it was my grandfathers, it is an original 1930 Model A town car. I noticed today when working on the car one of the front fenders has developed a crack. It is about an inch in length and runs vertically along the lip on the outside of the fender about directly above the hub cap. I have a few questions regarding this, first, is this common? It is something I may have done wrong to cause stress on the fender? Will it get worse or would it best to get it fixed? Like I said it is an original car so I hate to make too many major modifications or changes to the car but would hate for the crack to get worse. We drive and tour our cars so I want to make sure I don't cause any further issues with the fender. I appreciate any advise and information regarding the matter. Thank you in advance!