Rhogam shot

Hey! So I’m a negative blood type and I am supposed to get the rhogam shot on the 21st. I have a friend that is anti vax and of course she has told me not to get rhogam. I am not anti vax but she had added me to a group on Facebook and what people have said about it has me nervous. Can anyone offer any insight or if they have had it? I know what it is for, and everything I’ve read says that if you haven’t had anything traumatic to cause blood mixing if it’s your first pregnancy, that the chances are slim. That it is meant for future pregnancies. Any thoughts? Just feeling nervous about it. Thanks!!!