1 - don't be scared. it's hard to believe you can get cannabis in the mail like something from amazon but you can and unless you live in saudi arabia don't even sweat it for a second, no one gives a shit.
2 - bitcoins are a pain in the ass. getting your head around them conceptually is tougher than #1 but worth it. besides here you can use them to send money privately for your business or family without dealing with banks. it doesn't hurt to be ahead of the curve especially with finance. use the help resources here, they won't let you down.
3 - ratings are relative. like every rating system people are generally too kind or are total cunts and it resolves to a binary: 10 or not 10. this means a 9.9 is a ton better than a 9.4. if things are still too close to call read the reviews, they are legit, you can not write one unless you have bought the item.
4 - reach out to the community. if you need any help or have concerns come back here and post, it's the friendliest place you are going to find, trolls are not part of the culture but kindness is. it's also fun to read some of the crazier shit once you get your weed.