I want to learn cool BMX tricks but I always to nervous I’m going to hurt myself…Is there any tips to get rid of this? Or even some way to practice off the bike in a safer place?

You are going to be hurt, there is no way to avoid that, so what? You still got to do it right? Even if you end up with scrapped hands and knees now and them. The thing is that the more you relax the easier it gets not to fall so much. Learn to roll in a fall to use the energy instead of trying to stop.