I need help. Im under lots of peer pressure...?

Hi. Im a 14 year old guy that lives in Norman Oklahoma. All my freinds do weed. My girlfreind smokes it. My 2 best freinds do it. My mom used to do it. My favorite rapper (tupac) does it. So tell me, why shouldnt I. Idk im under lots of pressure. Not only that, but my girlfreind really wants to have and i do too, but i have no rubbers, and even if i did, idk if im ready. I could easily get weed but idk if i should. If i do start, how would i tell my mom. I would rather tell her that i did then get caught later. She used to do it alot. Not now though. My dads not here so i dont have to worry about him. But Idk im under so much pressure i cant stand it. I want to so bad. But i know its not right. Like for example, tonight at my freinds halloween party, My freind was trying to find a blunt and kid came up and fronted it. I wanted to toke out but i didnt. I need reasons why i shouldnt besides that its illegal and its bad for me. I need real reasons. Theres alot of stuff they cant teach you in school and this is one of them. also how old do you have to be to buy condoms?