I think everyone else just about covered it, except for one thing.
Lifting 1rms in the gym is a lot different to standing on a platform, in front of a room full of people, with three judges checking that your lift fit what many people think is quite a narrow technique criteria.
I've seen a lot of very strong people come to their first meet thinking they'll take out their class or whatever only to bomb out because they took too long to set up, or they didn't learn to use their gear properly before the meet, or they couldn't get their next attempt card in before the time limit expired, or not knowing what the calls mean, or any one of about a hundred little things that don't matter in the gym.
(Also, there's nothing more frustrating for meet officials than some FNG who doesn't have the first idea of where he's supposed to be, or what he's supposed to be doing)
Most people take time to adjust to lifting in a meet environment.
I'm not in any way trying to discourage you from competing. As a matter of fact, the sooner you compete, the better, imo.
I just think that you would do well to get hold of a rule book for whatever federation you plan on lifting in, read it a couple of time, maybe get hold of someone who's competed in that org and get them to show you the ropes. As other posters have said most people are more than happy to help out beginners.
Once you have a couple of meets under your (regulation thickness, approved manufacturer) belt not only will you be a lot stronger, your experience will benefit you a lot more than someone who trained for years, waiting until they got strong enough.
Good luck, and happy lifting.