I will only advise you to join if you know someone in the group or he person who taught you trading is also in the group then I you can join to get signal and trade. If not mate don't join, you will end up for been scammed. Though joining a trading signal group is one of the best way to learn trading. Through there you can learn more on different signals that you need to know for perfect trading. But not all the groups are legit.
Some are out there to scam. And one thing I will tell you is, when you join and you don't know anyone there and they ask you to pay, don't pay , they will use your money and close the group or remove you from the group. We have seen/heard many issues like that.
Learning before investing in the market, that's a solid activity. The best thing to avoid any issues is to be on our own, everything should be carried out by ourselves and strategy. We can't denied the fact that there are numerous scams in the system, we need to make good use of our initiative inother to prevent been victims of scams. Joining legit bitcoin groups for signals, is a good plan but these groups are not free, payment for these signals are made mandatory and it's not all the time one would record profits, sometimes the losses will surpassed the profits made.