Is it still technically racism if

I have a strong preference for white guys. I am a white person. I remember reading somewhere that people will often choose partners who match their genetics closest, so I think it would be natural to marry within ones own race.

No, racism is where you view a person as different or subhuman from another ethnic group. Mating preferences are different.

To the OP, not its not racism, its just preference, I prefer white girls, why? Because I just do, I’m around them more, I "know" them better, so I’m more inclined toward white females. I’m sure other races of women are just as good, but they’re just not for me.