In answer to your questions
1) No it isn't required, but things like Physics and Maths can help. Study hard and you'll be ok.
2) No, you're too old.. I started at 30
3) sorry can't help as never been to Raven air
4) First thing you should do is get your Class 1 medical, pass that then get you're PPL and then decide from there. You may fail the Class 1.. You may Struggle with the PPL, not saying you will but don't pin you're hopes on a career at the start.. Chances are though, you'll get the bug and love it..
5) Took me 15 months.. start to finish but I know others that worked part time and it took them 24 months.. It's not a race, and more important to pass everything 1st time than do it in record time. Don't pay up front, no need and any school worth it's money shouldn't ask you for it! There are plenty out that don't and don't be pressurised into it!
As said, get a trail flight, get you're medical and explore you're options as best you can... Work out a game plan and give it your best shot.. It was the best decision I ever made. Hard work, yes plenty of money and a lot of good luck..