Why doesnt my best friend belive I am dyslexic?

She kept saying she was dyslexic ( she has straight a's ) and I said no! your not...... 3 weeks ago she says to me I wish I was dyslexic i said why... you have no clue what they go with. she said I no but teachers would treat mee nicer. now she has been saying she suffers from dyslexia and I say no you don't. Tooday I told her I actullally am dyslexic she said no your not... then she called me a loser for not makeing honor roll and I said it is because I ams dyslexic she always calls me stupid and doesnt belive that I have dyslexia how unfair how can I get her to belive me so she wont call me stupid and a loser... she doesnt no what i am going through