I'm seeing the school nurse soon to make sure of this?

Well everything in my lofe is pointing towards me having ADHD and Dislexia so my mate is forcing me to the school nurse as my mum lafes at me or says horrible stuff to me every time i bring it up but the thing ig the more i search them up the more it does seem like it is true but im scared if 1 my mum knows i done a test without her knowing and 2 if i have got it and she wont belive me how should i get my mum to believe me and how should i deal with this if i have got it cose it is very important to me as i have thought i have had these for around 6-5 months and im 15 but i also don't have the best relationship with the school as i nearly got 2 teachers fired and in court and a bit more and also im addicted to fire i love setting them or stuff and i don't smoke or drink as 50% of my family have died because of smoking and drinking i just love fire why is that?!!? oh and i am carefull as i am a massive animal lover