Am i being selfish or is it ok?

im a 17 yr old girl who suffers from pcos ( polycystic ovarian syndrome) and one of my symptoms is hirsutisim ( my body is covered in manly dark hair including my stomach) i live in florida and we are about to have relitives visit in about a week i was talking to my dad asking if i could get a tankini to cover all my hair because im so self concious about it. he said yes when he gets his paycheck he would get it for me, well he got his paycheck and he was going to buy it until my mom started telling him "why do you always buy her stuff and not me" she already has a bathing suit. so as of now my dad will not be buying me a tankini, im heart broken because i am going to be beyond embaressed to show my face at the beach with my relitives, i dont have any money so i cant buy it myself. i just dont know what to do. im so depressed because of this hair issue....am i being selfish because i want this bathing suit so badly?