Ok, two words of advise:
1) not all players are friendly
2) wherever you go for a player group, keep in mind that players on the three platforms still can't directly interact, so it might help if you stated which platform you're on.
Most player groups interact on Discord. I occasionally hang out with the
Buckyball Racing Club (currently no specific ingame activity, although the Elite Racers are running their
8WD championship - and PrimetimeCasual is revving up for
Speedbowl IV), have been drawn into the abyss of
The Buur Pit and am currently spending most of my time with
Turning The Wheel.
Oh yes - thinking about player groups - if you have any specific preferences regarding languages or age bracket, there are player groups from all over the world (apart from English speaking countries, there are some very strong communities in the east European and Asian area) and catering to all age brackets. That includes player groups that would at least find it strange for anyone under 60 wanting to join them.