I've fallen in love wiv my maths teacher & i want to tell him on my last day at that school, how shud i do it?

So there's this teacher at my school &i had him 4 maths last year but i don't have him anymore. I'm 14 and he's 32 so there's a 18 year age gap between us. Technically i'm still in year 9 but we have recently begun our GCSE courses therefore have switched teachers-so before half term i had him for maths but unfortunately now i don't :( I just think he's incredibly fit and has a great personality, he's my dream guy and i've fallen in love with him. I don't plan to act on my feelings now but when i leave that school in approx.2 years i don't want to just try and forget about him because i won't be able to i want to tell him how i feel & i want u to plz tell me how exactly i shud do it & also plz give me a bit of advice over how to control my feelings for him right now cuz they r curently very strong. I have been in love with him now for approx.7 months & have kept my feelings to myself 4 most of that time however i recently told my frend about it.