Seriously OP?
I thought people stopped doing this when they were in primary school. I can just imagine it now, all you man children sticking your tongues out and counting on your fingers, yearning for an abacus or some sort of coloured chart while singing "Twinkle twinkle little star" in your head just to remember a ****ing letter.
This is what is wrong with the education system right here. What more evidence do you need?
Just testing, just testing ...erm.... dont you mean M-N?
I think it's fair to say that no matter what your age is, it is quite possible to not have any common sense. My dad is 50 odd, he can't even use a washing machine and gets his mum do the laundry! And guess what? He has a washing machine.
I do this with months. Whenever I need to do anything to do with months, I know that I'm right, but I have to run through it in my mind to check.