does the first time have to be special?

i’m having sex for the first time today with a fwb and I feel so comfortable around him, he treats me so well and we have such a close friendship but my sister is freaking her shit because “it has to be special and with the person you’re dating” and the first person she lost it too was dating her and ended up just breaking up with her afterwards anyways. sex doesn’t make someone stay with you, hell even a relationship doesn’t make someone stay with you. i’d rather be comfortable and trusting of the person to treat me well. that’s more important to me than the label. I guess I just want to see what everyone’s pov is on if the first time NEEDS to be this big special thing or if it’s just sex.