I wouldn't worry about it. If there is a problem, call KLM and explain it to them. If they don't tell you what you want to hear, call back and speak with a agent that is hopefully more helpful.
Are you flying into the states on KLM and then flying to your final destination on a different airline? If so, this is where possible problems could arise.
HOWEVER...however you look at it there is NOTHING you can do right now that won't cost you money. Most of the time there are no problems so the chances of you having a problem not great.
Also note...when you read about problems on here you also have to take into account how often people fly. If you're taking dozens or hundreds of flights per year, you're going to encounter a problem. Statistically you are going to be on one of those flights. An occasional flyer (like you) statistically is not likely to encounter a problem.
My advice:
-Go to KLM's and verify your reservation. Make sure everything is correct. Go to
www.seatguru.com and choose the best seats you are able to.
-Get to the airport early. Make sure you have proper documentation to get through immigration. KLM will want to check your documentation and if you don't have what you need, they will not let you board.
-If you can, don't check luggage (if the airlines don't touch your luggage they can't loose it...it isn't likely going to happen but it can happen).
-Be at the gate exactly when it says to on your boarding pass. Wait your turn to board. If they are boarding first class and you're traveling in economy, don't board.
-Be patient at all times
Have a good trip!