Different folks will give you different advice regarding their favorite beginner ships. I've been playing a while, but I still come back to my Diamondback Scout ("DBS") because it is so fun to fly. It's also one of the cheaper ships in the game. It does not have much cargo space, but it's a great courier runner, and excels with stuff like data hacks, salvage missions, etc.
Many people love the Cobra, and if you are interested in an inexpensive ship that can do many things well, it's a great early choice.
Regarding groups, and squadrons.... it depends alot on what you are looking to do. As with ships, there are many different squadrons out there. Most of them are very welcoming to new players. I happen to belong to one, and I can tell you we are recruiting, and very laid back. Even if you don't wind up joining a squadron, most of them are still cool with you asking questions or hanging out. My squadron forum page is here:
https://forums.frontier.co.uk/threads/wraith-shipping.565204/.