Afraid to have sex

Just need some advice. I'm bisexual, I think, or at least I really want to have sex with a man. I keep joining and deleting grindr, making engagements then backing out. I'm really anxious/afraid of having sex with a guy. What if I'm not gay or bi and have sex with a random guy who turns out has something and can't have a relationship! Just afraid to dip my toes in the pool...