is it normal? (yet another color at home Q)

hey everyone,

i have decided to color my hair at home since i ve been pretty much using the same color at the salon (dark brown) for a few years now, and i just need a touch up at the roots. (and salons are often quite disappointing)

i got a matrix so color dye and developer, but when i mixed it, it was yellow in color, is it normal? i assumed it was supposed to be dark, thats what i remember from having my hair done at the salon?

any advice/ reply would be so much appreciated. thanks!