For gas guns...
 

Where are you supposed to put the green gas/propane?
Is Co2 any good?
Where can I buy green gas?

propane+adaptor. If you insist on using green gas, I know triple H trading in edmonton sells them; they're rare in canada though because they're unnessesary.

Adapter?
What kind of adapter?

what gun are you asking about? or is it just "in general".

most real airsoft guns use propane/green gas some use duster gas. clearsoft gas guns use 12g co2 cartridges. for propane you use the AI adapter which can be bought at ASCMart link at the top of the page.

Alright, so what would you recommend to a newbie, gas or AEG?

AEG

Off topic but, how much would it hurt to get hit wearing normal clothing?

go to a game and find out, most people's perceptions of pain differ, you can also check out the different types of guns and decide which is best for you.

depends on the distance, FPS, BB type and weight, wind, temperature, your pain threshold... a shitload of stuff...

My god...though I should expect it hurts a lot right?

in outdoor cases, no... the risk is there for whatever sport you play... Ofcourse certain areas hurt like a bitch... your finger nails for instance; but yeah, if you don't want to run any risk, buy a mask or mouthguard, and some good quality gloves and boots.

Cool.

If you're serious about getting into the sport, then you can pick up some BDUs (battle dress uniforms) which are slightly thicker than normal clothes. They also have camo patterns which conceal you better than regular ass clothes which lowers your visibility and risk of getting shot at. Also a tactical vest would be good, as it serves the purpose of holding your mags and other useful stuff as well as putting an extra layer between the bb and your chest and back.

It's like sex.

It depends on the women, experience, protection/no protection, location Etc.. Etc... Etc...

TOO many factors to account for, just give it a go!

shoot yourself in the foot =D.
No, actually don't XD. Just go to a game.