The total you should aim for is whatever you can lift. Your first meet is more of a learning experience than anything else. Do not worry about where you will place, as competition is a whole new world.
If anyone laughs at you, they are only there as spectators. The other competitors will not only support your efforts, but will probably be able to provide advice that you may be in need of.
Don't worry about how you stack up against the opposition. The main thing is to do the best you can and try to break PR's. Once you get a few meets under your belt you can begin to concentrate on being more competitive. You will not be laughed at when you compete. If anything the spectators and other competitors will help you to achieve your goals. Powerlifting is more about beating the weight than beating the other guy.
If anyone laughs at you, they are only there as spectators. The other competitors will not only support your efforts, but will probably be able to provide advice that you may be in need of.
I nor have i ever seen anyone laugh at what someone lifts. Every new competetor is always welcome. Trust me bro it aint cool to laugh at someone who isnt lifting as much as you. Just lift learn and have fun. Take notes.