If I may, and I'll preface this by saying please don't take this the wrong way (or as my dad used to say, "This will hurt me more than it will hurt you")...
The boat has a weight limit not a weight suggestion. You should respect that limit.
You should also learn two very important skills before taking passengers out. One is how to right the boat when you capsize, and the other is crew overboard procedures. To do otherwise is irresponsible of the captain.
I don't mean to be a buzzkill, but the sea (small lakes included) is unforgiving and you don't have to be knocked down rounding the horn to have a bad day in a sailboat.
Please have fun, enjoy your new boat and enjoy learning your new rewarding hobby, but you'll have more fun longer if it's done safely.