I don't do baby cereal at all, there are a lot of reasons to skip it and fewer to do it. There are better ways to feed solids and better foods to do it with than the processed enriched cereals.
FWIW, our youngest kids were born the same month and I definitely wouldn't be starting solids at barely 5 months old.
I'd instead look into starting with fruits and vegetables, preferably ones she picks up and feeds herself (like mushy pieces of sweet potato or banana).
Mom of 4: Boy (10), Girl (7), Boy (4), Girl (2)