You should compete as soon as you can. One of two things will happen:
1.) You like the sport and you choose to pursue it. You meet people with similar goals. You have the opportunity to network with these people and you'll likely find guidance from more experienced lifters. Setting a competition date brings a certain bit of urgency and pragmatism to your training. For many it's extra motivation to train that much harder and get that much stronger.
2.) You compete and you figure out you hate powerlifting. Some people don't do well lifting in front of others. Some people like to lift weights but do not like to compete.
Either way there is no benefit to waiting.