If you buy the latest game with everything included, you'll be able to catch up incredibly quickly.
However, I'd just relax. Ignore the level booster for your first character and work through the story missions. Get to know the game systems, get a feel for the gunplay, etc...
People here often run low level characters. I just deleted my hunter and warlock to start over for the fun of it, for example.
You'll almost always be able to find someone to team up with here or on the Discord channel. Don't feel overwhelmed, this community is brilliant for helping our new players.
Feel free to add me if you decide to join us: astropoff.