Washing baby clothes.. ftm I need help!

Ok moms I need some help. We have been gifted an obscene amount of clothes. Do I wash all of the newborn and 0-3 month stuff we have been given? Do I wash just some of it? What is your advice? I also haven’t had an ultrasound since 20 weeks (except a 3D/4d and it didn’t measure anything) so I don’t know how “big” our baby might be. Also, stock up on newborn diapers or the size 1?

***suggestions on clothes you are gifted but don’t necessarily like? I’m grateful, but I feel like we will get more use of 0-3 than some of the newborn stuff