It's still a newly set up tank so I wouldn't worry too much about the nitrates. They aren't nearly as toxic to fish as ammonia and nitrIte are, and are actually good for the plants... just do a PWC any time they start really creeping up there. Once you get more plants in there, it's likely the problem will go away all together as the plants take them all in.
Your tank is just getting settled in. It will take a while for things to settle and for you to get a sense of what is and isn't normal. Just think things through and ask advice before making any major changes and you will do AWESOME. You're already doing VERY well!
