My guess is that since this is your "first batch" is that it is an extract kit. That means you probably added top off water to get to your desired fermenting volume. That said if you make and extract kit you should get what ever OG is listed w/the kit. What happened and happens a lot is you didn't get a good mix between your boil and toping off water. Don't worry, add your yeast, have a beer and relax.
NOW IMPORTANT INFO! Don't follow instructions if they tell you to move to a secondary in like 10 days or that your brew is done in 2 weeks or less and ready to bottle. Let the yeast work it's magic. Give your beer 3 weeks in the fermenter. Time to eat all the sugar, and then to clean up the wort and settle much of the trub to the bottom. Once you bottle let them sit for 3 weeks at about 70*F to fully carbonate.
